#include <bits/stdc++.h>
using namespace std;
int main() {
  long long x, y, n, a, b = -1;
  cin >> x >> y >> n;
  for (long long d = 1; d <= n; d++) {
    long long ini = 0, fim = n * x, m1, m2;
    while (ini + 2 < fim) {
      m1 = ini + (fim - ini) / 3;
      m2 = fim - (fim - ini) / 3;
      if (abs(x * d - m1 * y) < abs(x * d - m2 * y))
        fim = m2;
      else
        ini = m1;
    }
    long long val;
    if (abs(x * d - ini * y) <= abs(x * d - (ini + 1) * y) &&
        abs(x * d - ini * y) <= abs(x * d - fim * y))
      val = ini;
    else if (abs(x * d - (ini + 1) * y) <= abs(x * d - fim * y))
      val = ini + 1;
    else
      val = fim;
    if (b == -1 || b * abs(x * d - val * y) < d * abs(x * b - y * a)) {
      b = d;
      a = val;
    }
  }
  cout << a << '/' << b << endl;
  return 0;
}
