#include <bits/stdc++.h>

using i32 = std::int32_t;
using u32 = std::uint32_t;
using i64 = std::int64_t;
using u64 = std::uint64_t;
using i128 = __int128_t;
using u128 = __uint128_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

class rep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { ++itr; }
        constexpr bool operator!=(const Iter& other) const noexcept {
            return itr != other.itr;
        }
        constexpr usize operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr rep(const usize first, const usize last) noexcept
        : first(first), last(std::max(first, last)) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

template <class T> using Vec = std::vector<T>;

void A_main() {
    // 0, 1, 2, 3, 2
    // 1, 2, 3, 4, 3,
    // 2, 3, 4, 5, 4,
    u64 N;
    std::cin >> N;
    if (N <= 3) {
        std::cout << N << '\n';
    } else {
        std::cout << (N - 3) * 5 + 3 << '\n';
    }
    return;
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    A_main();
    return 0;
}