#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using std::cin;
using std::cout;
using std::vector;
using ll = long long;

int main() {
	int n, h, w;
	cin >> n >> h >> w;
	
	ll ans = 1ll * (n + 1) / 2 * n / 2 * (h + w - 2);
	cout << ans << '\n';
	
	return 0;
}