Constraints a and b are non-negative integers and can have maximum 200 digits.

public class Solution {

public static void main(String[] args) {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
    Scanner sc = new Scanner(System.in);
    BigInteger x = BigInteger.valueOf(0);
    BigInteger a = new BigInteger(sc.next());
    BigInteger b = new BigInteger(sc.next());

    if(a.bitLength() < 200 && b.bitLength() < 200 && x.compareTo(a) < 0 && x.compareTo(b) < 0) 
        System.out.println(a.add(b));
        System.out.println(a.multiply(b));

}

}