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 C (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <stdio.h>
int main(void)
{
	unsigned long long int num, sum=1;
	int lim, i;
    int flag1=0, flag2=0;
	scanf("%d", &lim);
	for (i = 0; i < lim; i++) {
		scanf("%lld", &num);
        if(num  > 1000000000000000000)
          flag1 = 1;
        if(num <= 1000000000000000000 / sum)
          sum *= num;
        if(num ==0)
          flag2=1;
	}
	if (flag2==1)
		printf("%d\n", 0);
	else if(flag1==1)
		printf("%d\n", -1);
    else 
        printf("%lld\n", sum);
	return 0;
}