#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n, h, w; cin >> n >> h >> w;
	int l = n / 2, r = l;
	if (n & 1) r++;
	long long p = 1LL * l * r;
	cout << p * (h + w - 2) << '\n';
	return 0;
}