#include <bits/stdc++.h>
using namespace std;
unsigned long long gcd(unsigned long long a, unsigned long long b) {
  while (b) {
    a %= b;
    swap(a, b);
  }
  return a;
}
unsigned long long lcm(unsigned long long a, unsigned long long b,
                       unsigned long long t) {
  unsigned long long tmp = (a / gcd(a, b));
  if (t / tmp >= b)
    return tmp * b;
  else
    return 0;
}
int main() {
  unsigned long long t, w, b;
  cin >> t >> w >> b;
  unsigned long long up;
  unsigned long long min1 = min(w, b) - 1;
  if (lcm(w, b, t) == 0) {
    up = min(min1, t);
  } else {
    up = (t / lcm(w, b, t)) + min1 * ((t / lcm(w, b, t))) +
         min(min1, t % lcm(w, b, t));
  }
  unsigned long long a = gcd(up, t);
  while (gcd(up, t) > 1) {
    a = gcd(up, t);
    up /= a;
    t /= a;
  }
  cout << up << "/" << t;
  return 0;
}
