#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, a, b, a1, b1, m, nod, k;
  cin >> n;
  cin >> a;
  cin >> b;
  if (a > n && b > n) {
    cout << '1' << '/' << '1';
    return 0;
  }
  if (a == b) {
    cout << '1' << '/' << '1';
    return 0;
  }
  if (n / a == 1 && n / b == 1 && n % a != 0 && n % b != 0) {
    k = min(a, b) - 1;
  } else {
    a1 = max(a, b);
    b1 = min(a, b);
    while (b1 > 0) {
      nod = a1 % b1;
      a1 = b1;
      b1 = nod;
    }
    nod = a1;
    if (n / b < a / nod) {
      k = min(a - 1, b - 1);
    } else {
      m = a / nod * b;
      k = min(a, b) * (n / m);
      k += min((n % m), min(a - 1, b - 1));
    }
  }
  a = n;
  b = k;
  while (true) {
    a = n;
    b = k;
    a1 = a;
    b1 = b;
    while (b1 > 0) {
      nod = a1 % b1;
      a1 = b1;
      b1 = nod;
    }
    nod = a1;
    n = a / nod;
    k = b / nod;
    if (a == n && b == k) break;
  }
  cout << b;
  cout << '/';
  cout << a;
  return 0;
}
