#include <bits/stdc++.h>
using namespace std;
const int INF = (int)2e9;
const long long INFL = (long long)9e18;
const int MAXINT = ((~0) ^ (1 << 31));
const long long MAXLL = ((~0) ^ ((long long)1 << 63));
template <class T>
inline T pow2(T a) {
  return a * a;
}
template <class T>
inline bool mineq(T& a, T b) {
  return (a > b) ? (a = b, true) : false;
}
template <class T>
inline bool maxeq(T& a, T b) {
  return (a < b) ? (a = b, true) : false;
}
unsigned long long gcd(unsigned long long a, unsigned long long b) {
  if (!b) return a;
  return gcd(b, a % b);
}
void answer(unsigned long long a, unsigned long long b) {
  if (a > b) a = b = 1;
  unsigned long long g = gcd(a, b);
  cout << a / g << "/" << b / g;
  exit(0);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  unsigned long long t, a, b;
  cin >> t >> a >> b;
  if (a > b) swap(a, b);
  unsigned long long g = gcd(a, b);
  if (a / g > t / b) answer(a - 1, t);
  unsigned long long lcm = a / g * b;
  unsigned 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);
}
