import java.math.*;
import javax.imageio.*;
import java.awt.image.*;
import java.awt.event.*;
import java.awt.*;
import java.security.spec.*;
import java.security.*;
import java.lang.management.*;
import java.lang.ref.*;
import java.lang.reflect.*;
import java.net.*;
import java.io.*;
import javax.swing.table.*;
import javax.swing.text.*;
import javax.swing.event.*;
import javax.swing.*;
import java.util.concurrent.atomic.*;
import java.util.concurrent.*;
import java.util.regex.*;
import java.util.List;
import java.util.zip.*;
import java.util.*;
public class main {

public static void main(String[] args) throws Exception {
  String s = "yes";
  print(collapseWord(toLowerCase(get(parse3(s), 1))));
}

static StringBuffer print_log;

static void print() {
  print("");
}

static void print(Object o) {
  String s = String.valueOf(o) + "\n";
  synchronized(StringBuffer.class) {
    if (print_log == null) print_log = new StringBuffer();
  }
  print_log.append(s);
  System.out.print(s);
}

static void print(long l) {
  print(String.valueOf(l));
}

static String[] toLowerCase(String[] strings) {
  String[] x = new String[l(strings)];
  for (int i = 0; i < l(strings); i++)
    x[i] = strings[i].toLowerCase();
  return x;
}

static String toLowerCase(String s) {
  return s == null ? "" : s.toLowerCase();
}

// get purpose 1: access a list/array (safer version of x.get(y))

static <A> A get(List<A> l, int idx) {
  return idx >= 0 && idx < l(l) ? l.get(idx) : null;
}

static <A> A get(A[] l, int idx) {
  return idx >= 0 && idx < l(l) ? l[idx] : null;
}

// get purpose 2: access a field by reflection

static Object get(Object o, String field) {
  if (o instanceof Class) return get((Class) o, field);
  
  if (o.getClass().getName().equals("main$DynamicObject"))
    return call(get_raw(o, "fieldValues"), "get", field);
    
  return get_raw(o, field);
}

static Object get_raw(Object o, String field) {
  try {
    Field f = get_findField(o.getClass(), field);
    f.setAccessible(true);
    return f.get(o);
  } catch (Exception e) {
    throw new RuntimeException(e);
  }
}

static Object get(Class c, String field) {
  try {
    Field f = get_findStaticField(c, field);
    f.setAccessible(true);
    return f.get(null);
  } catch (Exception e) {
    throw new RuntimeException(e);
  }
}

static Field get_findStaticField(Class<?> c, String field) {
  Class _c = c;
  do {
    for (Field f : _c.getDeclaredFields())
      if (f.getName().equals(field) && (f.getModifiers() & Modifier.STATIC) != 0)
        return f;
    _c = _c.getSuperclass();
  } while (_c != null);
  throw new RuntimeException("Static field '" + field + "' not found in " + c.getName());
}

static Field get_findField(Class<?> c, String field) {
  Class _c = c;
  do {
    for (Field f : _c.getDeclaredFields())
      if (f.getName().equals(field))
        return f;
    _c = _c.getSuperclass();
  } while (_c != null);
  throw new RuntimeException("Field '" + field + "' not found in " + c.getName());
}

  static List<String> parse3(String s) {
    return dropPunctuation(javaTokPlusPeriod(s));
  }

static String collapseWord(String s) {
  if (s == null) return "";
  StringBuilder buf = new StringBuilder();
  for (int i = 0; i < l(s); i++)
    if (i == 0 || s.charAt(i) != s.charAt(i-1))
      buf.append(s.charAt(i));
  return buf.toString();
}

  // varargs assignment fixer for a single string array argument
  static Object call(Object o, String method, String[] arg) {
    return call(o, method, new Object[] {arg});
  }
  
  static Object call(Object o, String method, Object... args) {
    try {
      if (o instanceof Class) {
        Method m = call_findStaticMethod((Class) o, method, args, false);
        m.setAccessible(true);
        return m.invoke(null, args);
      } else {
        Method m = call_findMethod(o, method, args, false);
        m.setAccessible(true);
        return m.invoke(o, args);
      }
    } catch (Exception e) {
      throw e instanceof RuntimeException ? (RuntimeException) e : new RuntimeException(e);
    }
  }

  static Method call_findStaticMethod(Class c, String method, Object[] args, boolean debug) {
    Class _c = c;
    while (c != null) {
      for (Method m : c.getDeclaredMethods()) {
        if (debug)
          System.out.println("Checking method " + m.getName() + " with " + m.getParameterTypes().length + " parameters");;
        if (!m.getName().equals(method)) {
          if (debug) System.out.println("Method name mismatch: " + method);
          continue;
        }

        if ((m.getModifiers() & Modifier.STATIC) == 0 || !call_checkArgs(m, args, debug))
          continue;

        return m;
      }
      c = c.getSuperclass();
    }
    throw new RuntimeException("Method '" + method + "' (static) with " + args.length + " parameter(s) not found in " + _c.getName());
  }

  static Method call_findMethod(Object o, String method, Object[] args, boolean debug) {
    Class c = o.getClass();
    while (c != null) {
      for (Method m : c.getDeclaredMethods()) {
        if (debug)
          System.out.println("Checking method " + m.getName() + " with " + m.getParameterTypes().length + " parameters");;
        if (m.getName().equals(method) && call_checkArgs(m, args, debug))
          return m;
      }
      c = c.getSuperclass();
    }
    throw new RuntimeException("Method '" + method + "' (non-static) with " + args.length + " parameter(s) not found in " + o.getClass().getName());
  }

  private static boolean call_checkArgs(Method m, Object[] args, boolean debug) {
    Class<?>[] types = m.getParameterTypes();
    if (types.length != args.length) {
      if (debug)
        System.out.println("Bad parameter length: " + args.length + " vs " + types.length);
      return false;
    }
    for (int i = 0; i < types.length; i++)
      if (!(args[i] == null || isInstanceX(types[i], args[i]))) {
        if (debug)
          System.out.println("Bad parameter " + i + ": " + args[i] + " vs " + types[i]);
        return false;
      }
    return true;
  }



static List<String> dropPunctuation_keep = litlist("*", "<", ">");

static List<String> dropPunctuation(List<String> tok) {
  tok = new ArrayList<String>(tok);
  for (int i = 1; i < tok.size(); i += 2) {
    String t = tok.get(i);
    if (t.length() == 1 && !Character.isLetter(t.charAt(0)) && !Character.isDigit(t.charAt(0)) && !dropPunctuation_keep.contains(t)) {
      tok.set(i-1, tok.get(i-1) + tok.get(i+1));
      tok.remove(i);
      tok.remove(i);
      i -= 2;
    }
  }
  return tok;
}

static String dropPunctuation(String s) {
  return join(dropPunctuation(nlTok(s)));
}

// This is made for NL parsing.
// It's javaTok extended with "..." token, "$n" and "#n" and
// special quotes (which are converted to normal ones).

static List<String> javaTokPlusPeriod(String s) {
  List<String> tok = new ArrayList<String>();
  int l = s.length();
  
  int i = 0;
  while (i < l) {
    int j = i;
    char c; String cc;
    
    // scan for whitespace
    while (j < l) {
      c = s.charAt(j);
      cc = s.substring(j, Math.min(j+2, l));
      if (c == ' ' || c == '\t' || c == '\r' || c == '\n')
        ++j;
      else if (cc.equals("/*")) {
        do ++j; while (j < l && !s.substring(j, Math.min(j+2, l)).equals("*/"));
        j = Math.min(j+2, l);
      } else if (cc.equals("//")) {
        do ++j; while (j < l && "\r\n".indexOf(s.charAt(j)) < 0);
      } else
        break;
    }
    
    tok.add(s.substring(i, j));
    i = j;
    if (i >= l) break;
    c = s.charAt(i);
    cc = s.substring(i, Math.min(i+2, l));

    // scan for non-whitespace
    if (c == '\u201C' || c == '\u201D') c = '"'; // normalize quotes
    if (c == '\'' || c == '"') {
      char opener = c;
      ++j;
      while (j < l) {
        char _c = s.charAt(j);
        if (_c == '\u201C' || _c == '\u201D') _c = '"'; // normalize quotes
        if (_c == opener) {
          ++j;
          break;
        } else if (s.charAt(j) == '\\' && j+1 < l)
          j += 2;
        else
          ++j;
      }
      if (j-1 >= i+1) {
        tok.add(opener + s.substring(i+1, j-1) + opener);
        i = j;
        continue;
      }
    } else if (Character.isJavaIdentifierStart(c))
      do ++j; while (j < l && (Character.isJavaIdentifierPart(s.charAt(j)) || s.charAt(j) == '\'')); // for things like "this one's"
    else if (Character.isDigit(c))
      do ++j; while (j < l && Character.isDigit(s.charAt(j)));
    else if (cc.equals("[[")) {
      do ++j; while (j+1 < l && !s.substring(j, j+2).equals("]]"));
      j = Math.min(j+2, l);
    } else if (s.substring(j, Math.min(j+3, l)).equals("..."))
      j += 3;
    else if (c == '$' || c == '#')
      do ++j; while (j < l && Character.isDigit(s.charAt(j)));
    else
      ++j;

    tok.add(s.substring(i, j));
    i = j;
  }
  
  if ((tok.size() % 2) == 0) tok.add("");
  return tok;
}


static int l(Object[] array) {
  return array == null ? 0 : array.length;
}

static int l(byte[] array) {
  return array == null ? 0 : array.length;
}

static int l(int[] array) {
  return array == null ? 0 : array.length;
}

static int l(Collection c) {
  return c == null ? 0 : c.size();
}

static int l(Map m) {
  return m == null ? 0 : m.size();
}

static int l(String s) {
  return s == null ? 0 : s.length();
} 



// extended over Class.isInstance() to handle primitive types
static boolean isInstanceX(Class type, Object arg) {
  if (type == boolean.class) return arg instanceof Boolean;
  if (type == int.class) return arg instanceof Integer;
  if (type == long.class) return arg instanceof Long;
  if (type == float.class) return arg instanceof Float;
  if (type == short.class) return arg instanceof Short;
  if (type == char.class) return arg instanceof Character;
  if (type == byte.class) return arg instanceof Byte;
  if (type == double.class) return arg instanceof Double;
  return type.isInstance(arg);
}

static List<String> nlTok(String s) {
  return javaTokPlusPeriod(s);
}

static <A> ArrayList<A> litlist(A... a) {
  return new ArrayList<A>(Arrays.asList(a));
}

  public static String join(String glue, Iterable<String> strings) {
    StringBuilder buf = new StringBuilder();
    Iterator<String> i = strings.iterator();
    if (i.hasNext()) {
      buf.append(i.next());
      while (i.hasNext())
        buf.append(glue).append(i.next());
    }
    return buf.toString();
  }
  
  public static String join(String glue, String[] strings) {
    return join(glue, Arrays.asList(strings));
  }
  
  public static String join(Iterable<String> strings) {
    return join("", strings);
  }
  
  public static String join(String[] strings) {
    return join("", strings);
  }

}