#include <bits/stdc++.h>
using namespace std;
const long double eps = 1.0e-12;
int GCD(int a, int b) {
  if (b) return GCD(b, a % b);
  return a;
}
int main() {
  int a, b, n, t, x, y;
  cin >> x >> y >> n;
  t = GCD(x, y);
  if (t > 1) {
    x /= t;
    y /= t;
  }
  if (y <= n) {
    a = x;
    b = y;
  } else {
    t = x / y;
    x %= y;
    long long x1 = 0, y1 = 1, x2 = 1, y2 = 1, xt = 0, xu = 1, yu;
    for (yu = 2; yu <= n; yu++) {
      if (xu * y - yu * x < 0) {
        xt = xu;
        xu++;
        if (xt * y1 - x1 * yu > 0) {
          x1 = xt;
          y1 = yu;
        }
      }
      if (xu * y2 - yu * x2 < 0) {
        x2 = xu;
        y2 = yu;
      }
    }
    if (1.0 * (x2 * y - x * y2) / y2 + eps < 1.0 * (x * y1 - y * x1) / y1) {
      a = x2 + t * y2;
      b = y2;
    } else {
      a = x1 + t * y1;
      b = y1;
    }
  }
  cout << a << "/" << b << endl;
  return 0;
}
