#include <bits/stdc++.h>
#include <iostream>
#include <string>
using namespace std;

int main() {
int a[6]={2,3,5,7,11,13};
int b[6]={4,6,8,9,10,12};
int c;
double count=0.0;
cin>>c;
for (int i = 0; i < 6; ++i) {
	for (int j = 0; j < 6; ++j) {
		if(c==a[i]*b[j]){
			count++;
		}
	}
}

printf("%.15f",count/36);

}


/*
2 1
3 7
4 11
5 71
6 111
7 711
8 1111
9 71111
10 11111
*/