UVa 11448 - Who said crisis?

// UVa 11448 - Who said crisis?

import java.math.BigInteger;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int tt = scanner.nextInt();
		for (int t = 0; t < tt; t++) {
			BigInteger a = scanner.nextBigInteger();
			BigInteger b = scanner.nextBigInteger();
			System.out.println(a.subtract(b));
		}

	}

}