#include <bits/stdc++.h>
using namespace std;
int main() {
  long long x, y, n, a = -1, b = -1, i, j;
  cin >> x >> y >> n;
  for (int i = 1; i <= n; i++) {
    j = i * x / y;
    j += ((i * x - y * j) > ((j + 1) * y - i * x)) ? 1 : 0;
    if (a == -1 || abs(a * y - x * b) * i > abs(j * y - x * i) * b)
      a = j, b = i;
  }
  cout << a << "/" << b << endl;
  return 0;
}
