#include "bits/stdc++.h"

// Begin {{{
using namespace std;
#define all(x) x.begin(), x.end()
#define rep(i, n) for (i64 i = 0, i##_limit = (n); i < i##_limit; ++i)
#define reps(i, b, e) for (i64 i = (b), i##_limit = (e); i <= i##_limit; ++i)
#define repr(i, b, e) for (i64 i = (b), i##_limit = (e); i >= i##_limit; --i)
#define var(Type, ...) Type __VA_ARGS__; input(__VA_ARGS__)
using i64 = int_fast64_t;
using pii = pair<i64, i64>;
template <class T> using MaxHeap = priority_queue<T>;
template <class T> using MinHeap = priority_queue<T, vector<T>, greater<>>;
template <class A, class B> inline bool chmax(A &a, const B &b) { return b > a && (a = b, true); }
template <class A, class B> inline bool chmin(A &a, const B &b) { return b < a && (a = b, true); }
inline i64 sigma(i64 n) { return n * (1 + n) >> 1; }
inline i64 updiv(i64 n, i64 d) { return (n + d - 1) / d; }
constexpr int INF = 0x3f3f3f3f;
constexpr i64 LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr int MOD = int(1e9) + 7;
#ifndef DEBUG
#define dump(...)
#endif

inline void input() {}
template <class Head, class... Tail>
inline void input(Head&& head, Tail&&... tail) {
    cin >> head;
    input(forward<Tail>(tail)...);
}

inline void outs() { cout << "\n"; }
template <class Head, class... Tail>
inline void outs(Head&& head, Tail&&... tail) {
    cout << head << (sizeof...(tail) ? " " : "");
    outs(forward<Tail>(tail)...);
}

template <class T>
inline void outs(vector<T> &vec) { for (auto &e : vec) cout << e << " \n"[&e == &vec.back()]; }

template <class T>
inline void outs(vector<vector<T>> &df) { for (auto &vec : df) outs(vec); }

inline void outl() { cout << "\n"; }
template <class Head, class... Tail>
inline void outl(Head&& head, Tail&&... tail) {
    cout << head << (sizeof...(tail) ? "\n" : "");
    outl(forward<Tail>(tail)...);
}

template <class T>
inline void outl(vector<T> &vec) { for (auto &e : vec) cout << e << "\n"; }

inline void outn() {}
template <class Head, class... Tail>
inline void outn(Head&& head, Tail&&... tail) {
    cout << head;
    outn(forward<Tail>(tail)...);
}

template <class T>
inline void outn(vector<T> &vec) { for (auto &e : vec) cout << e; }

template <class T>
inline vector<T> make_v(const T &initvalue, size_t sz) {
    return vector<T>(sz, initvalue);
}

template <class T, class... Args>
inline auto make_v(const T &initvalue, size_t sz, Args... args) {
    return vector<decltype(make_v<T>(initvalue, args...))>(sz, make_v<T>(initvalue, args...));
}
// }}} End

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    var(int, N);
    outn(fixed, setprecision(12));
    outl((double) 1 / N);
    return 0;
}