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 double autocorrelation(double[] voiceSample) {
  int n = voiceSample.length;
  double sum = 0;
  for (int j = 0; j < n; j++) {
    double correlation = 0;
    for (int i = 0; i < n; i++)
      correlation += voiceSample[i] * voiceSample[mod(i - j, n)];
    sum += correlation;
  }
  return doubleRatio(sum, n);
}
// better modulo that gives positive numbers always
static int mod(int n, int m) {
  return (n % m + m) % m;
}

static long mod(long n, long m) {
  return (n % m + m) % m;
}

static BigInteger mod(BigInteger n, int m) {
  return n.mod(bigint(m));
}

static double mod(double n, double m) {
  return (n % m + m) % m;
}

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


static BigInteger bigint(String s) {
  return new BigInteger(s);
}

static BigInteger bigint(long l) {
  return BigInteger.valueOf(l);
}

}