#include <bits/stdc++.h>

#define rep(i, n) for (int (i) = 0; (i) < (int)(n); (i)++)

const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int, int> pii;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int a[] = {2,3,5,7,11,13};
    int b[] = {4,6,8,9,10,12};
    double ans = 0;
    double tmp = 1./36;
    int K;
    cin >> K;
    for (int i = 0; i < 6; i++) for (int j = 0; j < 6; j++) {
        if (a[i]*b[j] == K) ans += tmp;
    }
    printf("%.15lf\n", ans);
    return 0;
}