#include <bits/stdc++.h>   using namespace std;   int gcd(int a, int b) {     if (b == 0) return a;     return gcd(b, a % b);   }   int main() {     int a, i, temp;     long long int sum = 0, n, fra;     cin >> a;     for (i = 2; i <= a - 1; i++) {       temp = a;       while (temp > 0) {         sum += temp % i;         temp = temp / i;       }     }     temp = a - 2;     fra = gcd(sum, temp);     while (fra != 1) {       sum = sum / fra;       temp = temp / fra;       fra = gcd(sum, temp);     }     cout << sum <<  /  << temp << endl;   }   