#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <algorithm>
#include <sstream>
#include <map>
#include <set>

#define REP(i,k,n) for(int i=k;i<n;i++)
#define rep(i,n) for(int i=0;i<n;i++)
#define INF 1<<30
#define pb push_back
#define mp make_pair

using namespace std;
typedef long long ll;
typedef pair<int,int> P;

int main() {
    int n;
    cin >> n;

    int a[6] = {2,3,5,7,11,13};
    int b[6] = {4,6,8,9,10,12};

    double ans = 0;
    rep(i,6) {
        rep(j,6) {
            if(a[i] * b[j] == n) {
                ans += 1.0 / 36;
            }
        }
    }

    cout << fixed;
    cout.precision(20);
    cout << ans << endl;

    return 0;
}