题目：http://acm.hdu.edu.cn/showproblem.php?pid=1002

import java.io.*;
import java.util.*; 
import java.math.*; 

public class Main{
	public static void main(String[] args){
		Scanner cin = new Scanner(System.in);
		int t=cin.nextInt();
		for(int i=1;i<=t;i++){
			BigInteger a = cin.nextBigInteger();
			BigInteger b = cin.nextBigInteger();
			System.out.println("Case "+i+":");		
			System.out.println(a+" + "+b+" = "+a.add(b));
			if(i<t){
				System.out.println();
			}
		}
	}
}