#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) {
  while (b != 0) {
    a = a % b;
    swap(a, b);
  }
  return a;
}
int main() {
  long long t = 0, a = 0, b = 0, tt = 0, ma = 0, aa = 0, lef = 0;
  cin >> t >> a >> b;
  tt = a / gcd(a, b);
  tt = t / tt / b;
  aa = tt * b;
  ma = min(a, b) - 1;
  lef = t - aa - min(a, b) + 1;
  tt *= min(a, b);
  if (t % (a / gcd(a, b) * b)) {
    tt += ma;
    if (lef < 0) tt += lef;
  }
  cout << tt / gcd(tt, t) << "/" << t / gcd(tt, t);
}
