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 (Clang 10.0.0) (judge verdict: Wrong Answer)

#include<stdio.h>

int main(){
  
 unsigned long long int n,b,i,ans;
  ans=1;
   
  (void) scanf("%llu",&n);
 
  for (i=0;i<n;i++)
  {
  (void) scanf("%llu",&b); 
   //printf("%llu\n",b);
    ans=ans*b;
    if (ans==0){
      printf("-1");
      return 0;
    }
    if (ans>=1000000000000000001)
    {
      printf("-1");
      return 0;
    }
  }
  
if(ans==0){
  printf("-1");
  return 0;
}  else{
   
 printf("%llu",ans);
}
 return 0; 
}