백준 #22193번 Multiply

import java.util.Scanner;
import java.math.BigInteger;
public class Main {
	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		int m = sc.nextInt();
		
		BigInteger a = sc.nextBigInteger();
		BigInteger b = sc.nextBigInteger();
		
		System.out.println(a.multiply(b));
		sc.close();
	}
}