#include <bits/stdc++.h>
using namespace std;
int main() {
  double x, y;
  int n, num, den, ta;
  double tmp, z = 10000005 * 1.0;
  cin >> x >> y;
  scanf("%d", &n);
  for (int b = 1; b < n + 1; ++b) {
    tmp = (x * b * 1.0) / (y * 1.0);
    ta = int(tmp + 0.5);
    for (int a = ta - 1; a <= ta + 1; a++) {
      tmp = abs(((x * 1.0) / (y * 1.0)) - ((a * 1.0) / (b * 1.0)));
      if (z > tmp) {
        z = tmp;
        num = a;
        den = b;
      }
    }
  }
  printf("%d/%d\n", num, den);
  return 0;
}
