Пропавшие слитки

#include <iostream>
#include <set>
using namespace std;
int main() {
    int n;
    cin >> n;
    long long a, b, c;
    cin >> a >> b >> c;
    set <long long> ans;
    long long count_cube_first, count_cube_second;
    for (count_cube_first = 0; count_cube_first <= n; count_cube_first++) {
        for (count_cube_second = n - count_cube_first; count_cube_second <= n; count_cube_second++) {
            long long height = count_cube_first * a + count_cube_second * b + (n - count_cube_first - count_cube_second) * c;
            ans.insert(height);
        }
    }
    cout << ans.size();
    return 0;
}