#include <bits/stdc++.h>   using namespace std;   int main() {     int a, k = 0, nod;     cin >> a;     for (int i = 2; i < a; i++) {       int b = a;       while (b != 0) {         k += b % i;         b /= i;       }     }     int b = a - 2;     for (int i = k; i > 0; i--)       if (k % i == 0 && b % i == 0) {         nod = i;         k /= nod;         b /= nod;         break;       }     cout << k <<  /  << b;   }   