#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
#include <queue>
#include <map>
#include <cmath>
#include <iomanip>

using namespace std;

const long long MOD = (long long)(1e9) + 7;

int main() {

  //cout << fixed << setprecision(15);

  long long n , h , w;
  cin >> n >> h >> w;
  long long ans;
  if (n % 2 == 0) {
    ans = (n / 2) * (n / 2) * (h - 1 + w - 1);
  } else {
    ans = (n / 2 + 1) * (n / 2) * (h - 1 + w - 1);
  }
  cout << ans << endl;
  
  return 0;
}