#include <bits/stdc++.h>
using namespace std;
long long min(long long a, long long b) { return a < b ? a : b; }
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
int main() {
  long long n, a, b;
  scanf("%I64d%I64d%I64d", &n, &a, &b);
  long long ans = 0;
  if (5000000000000000005 / a <= b / gcd(a, b)) {
    ans = min(a, b);
    ans = min(ans - 1, n);
    long long k = ans;
    printf("%I64d/%I64d\n", k / gcd(k, n), n / gcd(k, n));
  } else {
    long long k = a / gcd(a, b) * b;
    ans = n / k * min(a, b);
    if (n % k < min(a, b))
      ans += n % k;
    else
      ans += (min(a, b) - 1);
    long long u = gcd(n, ans);
    printf("%I64d/%I64d\n", ans / u, n / u);
  }
  return 0;
}
