#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int INF = 1000000000;
const ll INFL = 2e18;
template <class T>bool chmin(T &a, T b){ if (a > b) { a = b; return true;} else return false;}
template <class T>bool chmax(T &a, T b){ if (a < b) { a = b; return true;} else return false;}

int main() {
    int H,W,N;
    cin >> N >> H >> W;

    ll ans = 0;
    ans += (ll)(W - 1) * (N - N/2) * (N/2);
    ans += (ll)(H - 1) * (N - N/2) * (N/2);
    cout << ans << endl;
}