#include <bits/stdc++.h>
using namespace std;
long long uc(long long a, long long b) {
  if (!a) return 1ll;
  while (a != b) {
    if (a > b)
      a = a - b;
    else
      b = b - a;
  }
  return a;
}
int main() {
  long long x, y, n, i, a, b, t2, t, val;
  long long resa, resb;
  double res, tam;
  cin >> x >> y >> n;
  res = 200000000;
  for (i = 1ll; i <= n; i++) {
    b = i;
    val = b * x;
    t = val / y;
    a = t;
    t2 = val - t * y;
    if ((((t + 1) * y) - val) < t2) {
      t2 = ((t + 1) * y) - val;
      a = t + 1;
    }
    tam = ((double)t2) / ((double)(y * b));
    if (tam < res) {
      res = tam;
      resa = a;
      resb = b;
    }
  }
  t = uc(resa, resb);
  resa /= t;
  resb /= t;
  cout << resa << '/' << resb;
  return 0;
}
