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

static double digitalVariation(int[] array) {
  int n = l(array);
  if (n == 0) return 0; // ? - undefined
  if (n == 1) return 0;
  var value = array[0];
  int deviations = 0;
  for (int i = 1; i < n; i++)
    if (array[i] != value)
      ++deviations;
  return doubleRatio(deviations, n);
}

static <A> double digitalVariation(Iterable<A> l) {
  var it = iterator(l);
  if (!it.hasNext()) return 0; // ? - undefined
  int n = 1;
  var value = it.next();
  int deviations = 0;
  while (it.hasNext()) {
    ++n;
    if (!eq(value, it.hasNext()))
      ++deviations;
  }
  return doubleRatio(deviations, n);
}
static int l(Object[] a) { return a == null ? 0 : a.length; }
static int l(boolean[] a) { return a == null ? 0 : a.length; }
static int l(byte[] a) { return a == null ? 0 : a.length; }
static int l(short[] a) { return a == null ? 0 : a.length; }
static int l(long[] a) { return a == null ? 0 : a.length; }
static int l(int[] a) { return a == null ? 0 : a.length; }
static int l(float[] a) { return a == null ? 0 : a.length; }
static int l(double[] a) { return a == null ? 0 : a.length; }
static int l(char[] a) { return a == null ? 0 : a.length; }
static int l(Collection c) { return c == null ? 0 : c.size(); }

static int l(Iterator i) { return iteratorCount_int_close(i); } // consumes the iterator && closes it if possible

static int l(Map m) { return m == null ? 0 : m.size(); }
static int l(CharSequence s) { return s == null ? 0 : s.length(); }
static long l(File f) { return f == null ? 0 : f.length(); }



























static double doubleRatio(double x, double y) {
  return y == 0 ? 0 : x/y;
}




static <A> Iterator<A> iterator(Iterable<A> c) {
  return c == null ? emptyIterator() : c.iterator();
}


static boolean eq(Object a, Object b) {
  return a == b || a != null && b != null && a.equals(b);
}






static <A> int iteratorCount_int_close(Iterator<A> i) { try {
  int n = 0;
  if (i != null) while (i.hasNext()) { i.next(); ++n; }
  if (i instanceof AutoCloseable) ((AutoCloseable) i).close();
  return n;
} catch (Exception __e) { throw rethrow(__e); } }


static Iterator emptyIterator() {
  return Collections.emptyIterator();
}


static String str(Object o) {
  return o == null ? "null" : o.toString();
}

static String str(char[] c) {
  return new String(c);
}

static String str(char[] c, int offset, int count) {
  return new String(c, offset, count);
}




static RuntimeException rethrow(Throwable t) {
  
  if (t instanceof Error)
    _handleError((Error) t);
  
  throw t instanceof RuntimeException ? (RuntimeException) t : new RuntimeException(t);
}

static RuntimeException rethrow(String msg, Throwable t) {
  throw new RuntimeException(msg, t);
}




static void _handleError(Error e) {
  //call(javax(), '_handleError, e);
}



}