Two positive integer values a,b (a≧b) with 100 digits or less on standard input. A program that calculates the difference (a-b) and prints it to standard output.

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

public class Main {
    public static void main (String [] args) {
        Scanner scanner = new Scanner(System.in);
        String a = scanner.nextLine();
        String b = scanner.nextLine();
        BigInteger bigA = new BigInteger(a);
        BigInteger bigB = new BigInteger(b);
        System.out.println(bigA.subtract(bigB));
        
    }
}