#include <bits/stdc++.h>
#define NIL (-1)
#define ll long long
using namespace std;
const int64_t MOD = 1e9 + 7;
const int INF = INT_MAX;
const double PI = acos(-1.0);

int main() {
	ll N;
	cin >> N;

	if (N <= 3) cout << N << endl;
	else cout << (N - 3) * 5 + 3 << endl;
}