Combinations

#include <iostream>

using namespace std;

int main() {
    int n;
    cin >> n;

    int combinations = 0;

    for (int a = 0; a <= n; a++) {
        for (int b = 0; b <= n; b++) {
            for (int c = 0; c <= n; c++) {
                if (a + b + c == n) {
                    combinations++;
                }
            }
        }
    }

    cout << combinations << endl;
    return 0;
}