// Nachia くんだよ

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
using ll = long long;
using ull = unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)

int main() {
  ll N,H,W; cin >> N >> H >> W;
  H--; W--;
  ll c = N / 4;
  ll ans = (c*N/2 + c*(N%4)) * 2*(W+H);
  if(W < H) swap(W,H);
  if(N % 4 == 1) ans += W;
  if(N % 4 == 2) ans += H+W;
  if(N % 4 == 3) ans += 2 * (H+W);
  cout << ans << endl;
  return 0;
}


struct ios_do_not_sync{
  ios_do_not_sync(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
  }
} ios_do_not_sync_instance;