#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
int main() {
  int x, y, n;
  cin >> x >> y >> n;
  int a_ = -1, b_ = -1;
  long long p_ = INF, q_ = 1;
  for (int b = 1; b <= n; b++) {
    long long a = (long long)b * x / y;
    long long p = (long long)x * b - (long long)a * y, q = (long long)y * b;
    if (p < 0) p = -p;
    if (p_ * q > p * q_) {
      p_ = p, q_ = q;
      a_ = a;
      b_ = b;
    }
    a = ((long long)b * x + y - 1) / y;
    p = (long long)x * b - (long long)a * y, q = (long long)y * b;
    if (p < 0) p = -p;
    if (p_ * q > p * q_) {
      p_ = p, q_ = q;
      a_ = a;
      b_ = b;
    }
  }
  int d = gcd(a_, b_);
  a_ /= d, b_ /= d;
  cout << a_ << '/' << b_ << '\n';
  return 0;
}
