#include <bits/stdc++.h>
using namespace std;
int main() {
  long int m, n, l, k;
  long int i, j, x, y, s, z, w;
  int q, g;
  long int a[9999], b[9999];
  long int sum;
  while (scanf("%ld", &n) != EOF) {
    s = n - 2;
    w = n;
    l = n;
    sum = 0;
    for (i = w - 1; i >= 2; i--) {
      k = 0;
      n = l;
      while (n) {
        a[k] = n % i;
        k++;
        n = n / i;
      }
      for (; k >= 0; k--) {
        sum = sum + a[k];
      }
    }
    q = sum;
    g = s;
    while (1) {
      if (sum > s)
        sum = sum - s;
      else if (s > sum)
        s = s - sum;
      else {
        z = s;
        break;
      }
    }
    printf("%ld/%ld\n", q / z, g / z);
  }
}
