#include <bits/stdc++.h>
using namespace std;
int i;
double x, y, n, a, b, rsa, rsb = 1;
long long cmmdc(long long a, long long b) {
  while (a && b) (a > b ? a %= b : b %= a);
  return a + b;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin >> x >> y >> n;
  for (b = 1; b <= n; ++b) {
    a = max(0LL, (long long)(x * b / y) - 5);
    for (i = 0; i < 10; ++i, ++a) {
      double gmb = fabs(x * b - y * a) / (y * b);
      double fnc = fabs(x * rsb - y * rsa) / (y * rsb);
      if (gmb < fnc)
        rsb = b, rsa = a;
      else if (gmb == fnc && a / cmmdc(a, b) < rsa / cmmdc(rsa, rsb))
        rsa = a, rsb = b;
    }
  }
  long long ggg = cmmdc(rsa, rsb);
  cout << (long long)(rsa) / ggg << '/' << (long long)(rsb) / ggg << '\n';
  return 0;
}
