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 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 javax.imageio.*;
import java.math.*;
class main {

static class TimeCollector {
  long count, totalNanos;
  
  void addNanos(long nanos) {
    ++count;
    totalNanos += nanos;
  }
  
  public String toString() {
    return count == 0 ? "Empty time collector"
      : "Average time: " + formatElapsedTimeWithAppropriateUnit(nanosToSeconds(doubleRatio(totalNanos, count))) + " (n=" + count + ")";
  }
}
static String formatElapsedTimeWithAppropriateUnit(double seconds) {
  if (seconds >= 1) return formatDouble(seconds, 3) + " s";
  double ms = seconds*1000;
  if (ms >= 1) return formatDouble(ms, 3) + " ms";
  double us = ms*1000;
  if (us >= 1) return formatDouble(us, 3) + " µs";
  double ns = us*1000;
  return formatDouble(ns, 3) + " ns";
}
static double nanosToSeconds(double nanos) {
  return nanoSecondsToSeconds(nanos);
}
static double doubleRatio(double x, double y) {
  return y == 0 ? 0 : x/y;
}


static String formatDouble(double d, int digits) {
  String format = digits <= 0 ? "0" : "0." + rep(digits, '#');
  return decimalFormatEnglish(format, d);
}

static double nanoSecondsToSeconds(double nanos) {
  return nanos*1e-9;
}


static String rep(int n, char c) {
  return repeat(c, n);
}

static String rep(char c, int n) {
  return repeat(c, n);
}

static <A> List<A> rep(A a, int n) {
  return repeat(a, n);
}

static <A> List<A> rep(int n, A a) {
  return repeat(n, a);
}

static String decimalFormatEnglish(String format, double d) {
  return new java.text.DecimalFormat(format, new java.text.DecimalFormatSymbols(Locale.ENGLISH)).format(d);
}


static String repeat(char c, int n) {
  n = Math.max(n, 0);
  char[] chars = new char[n];
  for (int i = 0; i < n; i++)
    chars[i] = c;
  return new String(chars);
}

static <A> List<A> repeat(A a, int n) {
  n = Math.max(n, 0);
  List<A> l = new ArrayList(n);
  for (int i = 0; i < n; i++)
    l.add(a);
  return l;
}

static <A> List<A> repeat(int n, A a) {
  return repeat(a, n);
}

}