#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using ull=unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)

int main(){
  ll N; cin>>N;
  if(N>=3) cout<<((N-3)*5+3)<<"\n";
  else cout<<N<<"\n";
  return 0;
}