Help me in solving STJ12 problem

help
,
1

My issue

My code

/* The code below is incorrect. Debug this code to solve the problem */

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

class Codechef
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner kb=new Scanner(System.in);
		int n=kb.nextInt();int c=0;
		while(n!=0)
		{
		    int k=kb.nextInt();
		    String arr=kb.next();
		    String arr2=kb.next();
		    
		    for(int i=0;i<k;i++)
		    {
		        if(arr.charAt(i)!=arr2.charAt(i))
		        c++;
		    }
		    if(c%2==0)
		    System.out.println("0");
		    else
		    System.out.println("1");
		    n--;
		    c=0;
		}
	}
}

Learning course: Java for problem solving - 2
Problem Link: CodeChef: Practical coding for everyone