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: Accepted)

#include <stdio.h>

int main()
{
    int x[3]={0},i,maior=0,area=0;
    scanf("%d%d%d",&x[0],&x[1],&x[2]);
    for(i=0;i<3;i++)
    {
        if(x[i]>maior)
        {
            maior=x[i];
        }
    }

    if(x[0]==maior)
    {
        x[0]=1;
    }else if(x[1]==maior)
    {
        x[1]=1;
    }else if(x[2]==maior)
    {
        x[2]=1;
    }
    area=x[0]*x[1]*x[2]*1/2;
    printf("%d\n",area);

    return 0;
}