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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
public class Main {
	static int modAns = (int)Math.pow(10, 9) + 7;
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int length[] = new int[3];
		for(int i = 0; i < 3; i ++) {
			length[i] = sc.nextInt();
		}
		int max = Math.max(length[0], Math.max(length[1], length[2]));
		System.out.println(length[0] * length[1] * length[2] / max / 2);
	}
}