#include <bits/stdc++.h>
using namespace std;
int amenamec_ynd_bajanarar(int a, int b) {
  while (true) {
    if (b > a) {
      swap(a, b);
    }
    if (a % b == 0) {
      return b;
    }
    a %= b;
  }
}
int hamakarg(int a, int i) {
  int ans = 0;
  while (a != 0) {
    ans += a % i;
    a /= i;
  }
  return ans;
}
int main() {
  int a, ans = 0;
  cin >> a;
  for (int i = 2; i < a; i++) {
    ans += hamakarg(a, i);
  }
  cout << ans / amenamec_ynd_bajanarar(ans, a - 2) << "/"
       << (a - 2) / amenamec_ynd_bajanarar(ans, a - 2) << endl;
  return 0;
}
