Problem:
Score : 100 points

Problem Statement

In K-city, there are n streets running east-west, and m streets running north-south. Each street running east-west and each street running north-south cross each other. We will call the smallest area that is surrounded by four streets a block. How many blocks there are in K-city?

Constraints

2 ≤ n, m ≤ 100

Input

Input is given from Standard Input in the following format:

n m

Output

Print the number of blocks in K-city.

Sample Input 1

3 4

Sample Output 1

6

There are six blocks, as shown below:

Sample Input 2

2 2

Sample Output 2

1

There are one block, as shown below:

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

#include<stdio.h>
int main(void){
  int i;
  char s[101];
  int ct=0;
  
  for(i=0;i<101;i++){
    s[i]=0;
  }
  
  for(i=0;i<101;i++){
    scanf("%c",&s[i]);
  }
  
  for(i=0;i<101;i++){
    if(s[i] != '0')ct++;
    else break;
  }
  
  printf("%c%d%c\n",s[0],ct-2,s[ct-1]);
  
  return 0;
}