#include <bits/stdc++.h>
using namespace std;
long long GCD(long long a, long long b) {
  long long t;
  while (b) {
    t = a % b;
    a = b;
    b = t;
  }
  return a;
}
void Solve() {
  long long a, b, i, j;
  long long x, y;
  long long n, m;
  double ans = 0x7fffffff, res, z;
  scanf("%I64d%I64d%I64d", &x, &y, &n);
  m = GCD(x, y);
  x /= m;
  y /= m;
  if (n >= y)
    a = x, b = y;
  else {
    z = (double)x / y;
    for (i = 1; i <= n; ++i) {
      j = i * x / y;
      res = (double)j / i - z;
      res = (res < 0 ? -res : res);
      if (ans - res > 1e-15)
        a = j, b = i, ans = res;
      else if (ans - res <= 1e-15) {
        if (b == i)
          a = (a < j ? a : j);
        else if (i < b)
          b = i, a = j;
      }
      ++j;
      res = (double)j / i - z;
      res = (res < 0 ? -res : res);
      if (ans - res > 1e-15)
        a = j, b = i, ans = res;
      else if (ans - res <= 1e-15) {
        if (b == i)
          a = (a < j ? a : j);
        else if (i < b)
          b = i, a = j;
      }
    }
  }
  m = GCD(a, b);
  printf("%I64d/%I64d\n", (a / m), (b / m));
}
int main() {
  Solve();
  return 0;
}
