#include "bits/stdc++.h" //#define int long long using namespace std; using ll = long long; using P = pair; const ll INF = (1LL << 61); ll mod = 1000000007; signed main() { ios::sync_with_stdio(false); cin.tie(0); ll N; cin >> N; if (N == 1)cout << 1 << endl; else if (N == 2)cout << 2 << endl; else if (N == 3)cout << 3 << endl; else { int now = 7; now += (N - 4) * 5; now++; cout << now << endl; } return 0; }