/* -*- coding: utf-8 -*-
 *
 * 1603.cc:  No.1603 Manhattan Social Distance - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

/* main */

int main() {
  int n, h, w;
  scanf("%d%d%d", &n, &h, &w);

  int l = (h - 1) + (w - 1);
  ll c = (ll)(n / 2) * (n - n / 2) * l;
  printf("%lld\n", c);
  return 0;
}