#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)
#define P pair<int, int>

int main() {
  ll n, h, w;
  cin >> n >> h >> w;
  ll k = n/2;
  ll ans = k*(n-k)*(h+w-2);
  cout << ans << endl;


}