#include <bits/stdc++.h>
using namespace std;
long long tfc, w, b;
long long gcd(long long a, long long b) { return !b ? a : gcd(b, a % b); }
void cod() {
  if (w == b) {
    printf("1/1");
    return;
  }
  if (w > b) {
    long long temp = w;
    w = b;
    b = temp;
  }
  if (1 == w) {
    long long numbera = tfc / b;
    long long d = gcd(numbera, tfc);
    printf("%lld/%lld", (numbera / d), (tfc / d));
    return;
  }
  long long d = gcd(w, b);
  if ((1.0f * tfc / b) < (1.0f * w / d)) {
    long long numbera = min(w - 1, tfc);
    d = gcd(numbera, tfc);
    printf("%lld/%lld", (numbera / d), (tfc / d));
    return;
  }
  long long m = w / d * b;
  long long numbera = (tfc / m) * w;
  long long res = tfc % m;
  numbera += min(w - 1, res);
  d = gcd(numbera, tfc);
  printf("%lld/%lld", (numbera / d), (tfc / d));
  return;
}
int main() {
  while (cin >> tfc >> w >> b) {
    cod();
    cout << endl;
  }
  return 0;
}
