#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) {
  if (a == 0) return b;
  return gcd(b % a, a);
}
void prin(long long a, long long b) {
  long long c = gcd(a, b);
  cout << a / c << "/" << b / c << endl;
}
int main() {
  std::ios_base::sync_with_stdio(false);
  long long a, b, c, d, e, f, g, h;
  cin >> a >> b >> c;
  if (a < min(b, c)) {
    cout << "1/1\n";
    return 0;
  }
  long long ans1, ans2;
  ans2 = a;
  ans1 = min(b, c) - 1;
  d = gcd(c, b);
  e = b / d;
  if (e == (a / c) && a % c == 0) {
    ans1++;
    prin(ans1, ans2);
    return 0;
  } else if (e > (a / c)) {
    prin(ans1, ans2);
    return 0;
  } else {
    f = a / (e * c);
    g = min(b, c) - 1;
    h = a % (e * c);
    ans1 += (f * (g + 1));
    if (h < g) ans1 -= (g - h);
    prin(ans1, ans2);
  }
  return 0;
}
