Problem:
Score : 100 points

Problem Statement

There is a right triangle ABC with ∠ABC=90°.

Given the lengths of the three sides, |AB|,|BC| and |CA|, find the area of the right triangle ABC.

It is guaranteed that the area of the triangle ABC is an integer.

Constraints

1 \leq |AB|,|BC|,|CA| \leq 100

All values in input are integers.

The area of the triangle ABC is an integer.

Input

Input is given from Standard Input in the following format:

|AB| |BC| |CA|

Output

Print the area of the triangle ABC.

Sample Input 1

3 4 5

Sample Output 1

6

This triangle has an area of 6.

Sample Input 2

5 12 13

Sample Output 2

30

This triangle has an area of 30.

Sample Input 3

45 28 53

Sample Output 3

630

This triangle has an area of 630.

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)


#include <stdio.h>

int main()
{
  int a, b, c;
  int max, mid, min;

  scanf("%d %d %d", &a, &b, &c);
  if (a>b) {
    max = a;
    mid = c;
    min = b;
  } else {
    max = b;
    mid = c;
    min = a;
  }
  if (a > c) {
  } else {
    mid = a;
  }
  printf("%d\n", (mid * min)/2);
  return 0;
}