#include <iostream>

using namespace std;
using lint = long long;

void solve() {
    lint n;
    cin >> n;
    cout << (n < 3 ? n : (n - 3) * 5 + 3) << "\n";
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    solve();

    return 0;
}