#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

int main() {
    
    double a = 0;
    int p[6] = { 2,3,5,7,11,13 };
    int c[6] = { 4,6,8,9,10,12 };
    
    int K;
    cin >> K;
    
    for ( int i = 0; i < 6; i++ ) {
    for ( int j = 0; j < 6; j++ ) {
        if ( p[i] * c[j] == K ) {
            a++;
        }
    }
    }
    
    printf( "%.13f", a / 36.0 );
    
    
    return 0;
}