#include<iostream> #include<cstdio> #include<cstring> #include<string> #include<cctype> #include<cstdlib> #include<algorithm> #include<bitset> #include<vector> #include<list> #include<deque> #include<queue> #include<map> #include<set> #include<stack> #include<cmath> #include<sstream> #include<fstream> #include<iomanip> #include<ctime> #include<complex> #include<functional> #include<climits> #include<cassert> #include<iterator> #include<unordered_map> #include<unordered_set> using namespace std; int a[] = { 2, 3, 5, 7, 11, 13 }; int b[] = { 4, 6, 8, 9, 10, 12 }; int main(){ int countt = 0; int k; cin >> k; for (int i = 0; i < 6; i++){ for (int j = 0; j < 6; j++){ if (a[i] * b[j] == k){ countt++; } } } double a = countt; double b = 6 * 6; a /= b; printf("%.16f\n", a); return 0; }