// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
// #include <boost/multi_array.hpp>
// #include <boost/optional.hpp>
// #include <boost/range/irange.hpp>
// #include <boost/range/algorithm.hpp>
// #include <boost/range/adaptors.hpp>
#include <atcoder/all>

using namespace std;
using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep2(i, x, n) for (int i = x; i < (n); i++)
#define all(n) begin(n), end(n)
const int INF = 1e9;
const long long llINF = 1LL << 60;

#define endl '\n'
#define yn(a) cout << ((a) ? "yes" : "no") << endl
#define YN(a) cout << ((a) ? "YES" : "NO") << endl
// using int = ll;

int dy[] = {0, 0, 1, -1};
int dx[] = {1, -1, 0, 0};

void Solve() {
    ll n;
    cin >> n;
    if (n <= 3) cout << n << endl;
    else {
        n -= 3;
        cout << 3 + n * 5 << endl;
    }
}

int main() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << std::fixed << std::setprecision(15);
    Solve();
    return 0;
}