#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define reps(i, s, n) for(ll i = (s), i##_len = (n); i < i##_len; i++)
#define rrep(i, n) for(ll i = (n) - 1; i >= 0; i--)
#define rreps(i, e, n) for(ll i = (n) - 1; i >= (e); i--)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((ll)(x).size())
#define len(x) ((ll)(x).length())

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // ifstream in("input.txt");
    // cin.rdbuf(in.rdbuf());
    ll k;
    cin >> k;
    ll s[] = {2,3,5,7,11,13};
    ll g[] = {4,6,8,9,10,12};
    ll cnt = 0;
    rep(i, 6) {
        rep(ii, 6) {
            if ((s[i] * g[ii]) == k) cnt++;
        }
    }
    double ans = cnt / (36.0);
    printf("%.18f\n", ans);
    return 0;
}