#include <iostream>
using namespace std;

int main() {
    int k;
    cin >> k;
    int s[6] = {2,3,5,7,11,13},g[6] = {4,6,8,9,10,12};
    double ans=0;
    for(int i = 0;i < 6;i++){
        if(k%s[i] == 0)
            for(int j = 0;j < 6;j++){
                if(k/s[i] == g[j])ans += 0.0277777777777777778;
            }
    }
    printf("%.13f\n",ans);
return 0;
}