#include<algorithm>
#include<iostream>
#include<vector>
#include<map>
#include<cassert>
using namespace std;
using ll = long long;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    ll n,h,w;
    cin>>n>>h>>w;

    ll m = n / 2;
    ll a = n - m;
    ll ans = (h-1+w-1) * m * a;
    cout<<ans<<endl;
}