#include <iostream>
#include <cassert>
#include <vector>
#include <algorithm>

using namespace std;

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

  long long N; cin >> N;
  if (N <= 3) {
    cout << N << endl;
    return 0;
  }
  
  long long t = (N - 3) * 5;
  cout << t + 3 << endl;
  return 0;
}