Domino Piles

Source Code:

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int a,b,c,d;
    cin>>a>>b;
    c=a*b;
    d=c/2;
    cout<<d;
    return 0;
}