/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{

int[] spam = new int[] { 1, 2, 3,1 };
containsDuplicate(spam);

System.out.println( new HashSet<>( ) ) ;

	}
	  public static boolean containsDuplicate(int[] nums) {
        System.out.println((Arrays.asList(nums)).size());
        return new HashSet<>(Arrays.asList(nums)).size() !=nums.length;
        
    }
}