#include <bits/stdc++.h>
using namespace std;
double ghadr(double g) {
  if (g < 0) g = -g;
  return g;
}
int main() {
  long double c = double(1) / double(2), d, chert, ans = 1e8;
  long long x, y, n, a, b, tmp;
  cin >> x >> y >> n;
  for (int i = n; i > 0; i--) {
    d = double(x) / double(y);
    d *= i;
    d += c;
    tmp = d;
    chert = tmp;
    if (chert == d)
      if (tmp > 0) tmp--;
    if (ans >= ghadr(double(double(x * i) - double(tmp * y)) / double(y * i))) {
      ans = ghadr(double(double(x * i) - double(tmp * y)) / double(y * i));
      a = tmp;
      b = i;
    }
  }
  cout << a << "/" << b << endl;
  return 0;
}
