#include <iostream>
#include <iomanip>
using namespace std;

int main(){
   int k,n = 0;
   const int PRIME[] = {2,3,5,7,11,13},COMPOSITE[] = {4,6,8,9,10,12};
   cin >> k;
   for(int i = 0;i < 6;i++) for(int j = 0;j < 6;j++) if(k == PRIME[i] * COMPOSITE[j]) n++;
   cout << fixed << setprecision(13) << n / 36.0 << endl;
}