#include <bits/stdc++.h>
using namespace std;
long long n, m, a[1000100];
long long gcd(long long x, long long y) { return (y == 0) ? x : gcd(y, x % y); }
int main() {
  long long c, r, k, i, x = 0, y = 0, j, t, l, z, x1 = 0, y1 = 0, bm = 1000100,
                        wm = 1000100;
  long long ans = 0;
  string p;
  scanf("%lld %lld", &z, &y);
  scanf("%lld", &x);
  l = gcd(x, y);
  r = min(x, y);
  c = (long long)(((double)x * y) / l);
  i = r * (z / c) - 1 + min(z % c + 1, r);
  j = gcd(i, z);
  i /= j;
  z /= j;
  cout << i << "/" << z << endl;
  return 0;
}
