#include <bits/stdc++.h>
using namespace std;
int main() {
  long long x, y, n;
  cin >> x >> y >> n;
  long long a0 = 100000, b0 = 1;
  long long a1, b1, a2, b2, a, b, p;
  for (int i = 1; i <= n; i++) {
    p = i * x / y;
    for (int j = 1; j <= 2; j++, p++) {
      a1 = p * y - i * x;
      if (a1 < 0) a1 = -a1;
      b1 = i * y;
      if (a0 * b1 - b0 * a1 > 0) {
        a0 = a1;
        b0 = b1;
        a = p;
        b = i;
      }
    }
  }
  cout << a << '/' << b << endl;
  return 0;
}
