View Code of Problem 3689

import java.math.BigInteger;
import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int t = sc.nextInt();
    int k = 1;
    while (t>0){
      --t;
      BigInteger a = sc.nextBigInteger();
      BigInteger b = sc.nextBigInteger();
      System.out.println("Case #"+ k++ +":");
      System.out.println(a.subtract(b));
    }
  }
}