#include <bits/stdc++.h>
using namespace std;
unsigned long long gcd(unsigned long long x, unsigned long long y) {
  unsigned long long r;
  while (y) {
    r = x % y;
    x = y;
    y = r;
  }
  return x;
}
int main() {
  std::ios_base::sync_with_stdio(false);
  unsigned long long t, b, w;
  cin >> t >> b >> w;
  if (b > w) swap(b, w);
  unsigned long long g = gcd(b, w);
  long double tt;
  tt = t;
  long double bb = b;
  unsigned long long nr = w / g;
  long double nrnr = nr;
  long double f = tt / bb;
  if (nrnr > f) {
    unsigned long long x, y;
    x = min(b - 1, t);
    y = t;
    g = gcd(x, y);
    x /= g;
    y /= g;
    cout << x << "/" << y << "\n";
    return 0;
  } else {
    nr = w / g;
    nr = nr * b;
    unsigned long long m = nr;
    unsigned long long x = (t / m) * b + min(t % m, b - 1);
    unsigned long long y = t;
    g = gcd(x, y);
    x /= g;
    y /= g;
    cout << x << "/" << y << "\n";
  }
  return 0;
}
