#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
#include<set>
#include<bitset>
#include<math.h>
#include<map>
#include<queue>
#include<iomanip>
using namespace std;

int main(){
    int n, cnt = 0;
    cin >> n;
    vector<int> a = {2, 3, 5, 7, 11, 13}, b = {4, 6, 8, 9, 10, 12};
    for (int i = 0; i < 6; i++){
        for (int j = 0; j < 6; j++){
            if (a[i] * b[j] == n) cnt++;
        }
    }
    cout << fixed << setprecision(13) << cnt/36. << endl;
}