#include <bits/stdc++.h>
using namespace std;
int x, y, n, v, g, h;
double f, a[100005], MIN;
double ABS(double d) {
  if (d < 0)
    return -d;
  else
    return d;
}
int gcd(int a, int b) {
  if (a < b) return gcd(b, a);
  return b == 0 ? a : gcd(b, a % b);
}
int main() {
  MIN = 100000;
  scanf("%d%d%d", &x, &y, &n);
  f = x / (double)y;
  for (int i = 1; i <= n; i++) a[i] = f * i;
  for (int i = 1; i <= n; i++) {
    int tmp = (int)a[i];
    double x1, x2, x3;
    x1 = (tmp - 1) / (double)i;
    x2 = (tmp) / (double)i;
    x3 = (tmp + 1) / (double)i;
    if (ABS(x1 - f) < MIN) {
      g = tmp - 1;
      h = i;
      MIN = ABS(x1 - f);
    }
    if (ABS(x2 - f) < MIN) {
      g = tmp;
      h = i;
      MIN = ABS(x2 - f);
    }
    if (ABS(x3 - f) < MIN) {
      g = tmp + 1;
      h = i;
      MIN = ABS(x3 - f);
    }
  }
  int div = gcd(g, h);
  g /= div;
  h /= div;
  printf("%d/%d\n", g, h);
  scanf("\n");
  return 0;
}
