#include <bits/stdc++.h>
using namespace std;
long long n, t, a, b, tmp, lcm, ans = 0, makh, k;
long long gcd(long long a, long long b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
void answer(long long a, long long b) {
  if (a > b) a = b = 1;
  long long g = gcd(a, b);
  cout << a / g << "/" << b / g;
  exit(0);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> t >> a >> b;
  if (a > b) swap(a, b);
  long long g = gcd(a, b);
  if (a / g > t / b) answer(a - 1, t);
  long long lcm = a / g * b;
  long long ans = (t / lcm + 1) * a;
  if (t / lcm * lcm + a - 1 >= t) ans -= t / lcm * lcm + a - t - 1;
  answer(ans - 1, t);
}
