#include <iostream>
#include <iomanip>

#include <algorithm>
#include <math.h>

#include <string>
#include <list>
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

int main(void){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed;//
    cout << setprecision(13);//

	int K;
	cin>>K;
	int s[6] ={2,3,5,7,11,13};
	int g[6] ={4,6,8,9,10,12};

	int x[36];
	int count=0;
	rep(i,36){
		x[i] = s[i%6]*g[i/6];
		if(x[i] == K){
			++count;
		}
	}
	P(1.0*count/36.0);
    return 0;
}