Problem:
Score : 100 points

Problem Statement

Compute A \times B.

Constraints

1 \leq A \leq 100

1 \leq B \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B

Output

Print the value A \times B as an integer.

Sample Input 1

2 5

Sample Output 1

10

We have 2 \times 5 = 10.

Sample Input 2

100 100

Sample Output 2

10000

Solution in Java (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		// 整数の数
		long N = scan.nextLong();

		long ans = 1;
		List<Long>  list = new ArrayList();

		for(int i = 0; i < N; i++) {
			list.add(scan.nextLong());
		}

		// 0が含まれていたら
		if(list.contains(0)) {
			System.out.println(0);
			return;
		}

		for(int i = 0; i < list.size(); i++) {
			ans = ans * list.get(i);
		}

		if(ans > 1000000000000000000l) {
			System.out.println(-1);
		}else {
			System.out.println(ans);
		}

	}

}