#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    vector<int> s = {2,3,5,7,11,13};
    vector<int> g = {4,6,8,9,10,12};
    int k;
    cin >> k;
    double count = 0;
    for(int i = 0; i < 6;i++){
        if(k % s[i] != 0)continue;
        int test = k / s[i];
        for(int j = 0;j < 6;j++){
            if(test == g[j])count++;
        }
    }
    printf("%.12lf\n",count/36);
    return 0;
}