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 <bits/stdc++.h> 
using namespace std; 
#define rep(i,a,b)		for(int i=a;i<=b;i++)
const long long INF = 1e18;
long long ans,n;
int main() 
{ 

	ios::sync_with_stdio(false);
    cin.tie(NULL);
    cin>>n;
    vector<long long> arr(n);

   	rep(i,0,n-1)
   	{
   		cin>>arr[i];
   		if(arr[i]==0)
   		{
   			cout<<0<<endl;
   			return 0;
   		}
   	}

   	ans = 1;
   	for(int i=0;i<n;i++)
   	{
   		if(ans<=INF/arr[i])
   			ans*=arr[i];
   		else
   		{
   			cout<<-1<<endl;
   			return 0;
   		}
   	}
   	cout<<ans<<endl;
   	return 0;
}