#include <bits/stdc++.h>
using namespace std;

#define repeat(i, x) for (int64_t i = 0; (i) < (int64_t)(x); (i)++)

namespace TaskC {
    void solve() {
        int n;
        cin >> n;

        cout.precision(10);
        if (n <= 7) {
            int num = 1;
            repeat (i, n) num *= 10;
            cout << (double)(num / 7) / (double)num << endl;
        } else {
            cout << 1.0 / 7.0 << endl;
        }
    }
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    TaskC::solve();

    return 0;
}