View Code of Problem 3689

import java.math.BigInteger;
import java.util.*;
 
public class Main{
    public static void main(String[] args){
        Scanner input = new Scanner(System.in);
        int t = input.nextInt();
        int k = 1;
        for(int i = 0 ; i < t; i++){
            BigInteger a = input.nextBigInteger();
            BigInteger b = input.nextBigInteger();
            System.out.println("Case #"+ k++ +":");
            System.out.println(a.subtract(b));
        }
    }
}