#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;
}
void refine(unsigned long long &a, unsigned long long &b) {
  unsigned long long g = gcd(a, b);
  a /= g;
  b /= g;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  unsigned long long t, a, b;
  cin >> t >> a >> b;
  unsigned long long g = gcd(a, b);
  unsigned long long aa = a / g;
  if (aa > t / b) {
    unsigned long long numer = min(min(a, b) - 1, t);
    unsigned long long denom = t;
    refine(numer, denom);
    cout << numer << '/' << denom << endl;
    return 0;
  }
  unsigned long long lcm = aa * b;
  unsigned long long numer = (t / lcm + 1) * min(a, b) - 1;
  if (t % lcm < min(a, b)) numer -= min(a, b) - t % lcm - 1;
  unsigned long long denom = t;
  refine(numer, denom);
  cout << numer << '/' << denom << endl;
  return 0;
}
