Help me in solving MEXPROB problem

My issue

help me in solving

My code

/* package codechef; // 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 Codechef
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
	}
}

Problem Link: MEXPROB Problem - CodeChef