#include <bits/stdc++.h>
using namespace std;
int gcd(int a, int b) {
  int t = 0;
  while (b) {
    t = a % b;
    a = b;
    b = t;
  }
  return a;
}
void solve(int &a, int &b) {
  int d = gcd(a, b);
  while (d != 1) {
    a /= d;
    b /= d;
    d = gcd(a, b);
  }
}
int main() {
  int i = 0, j = 0, x = 0, y = 0, n = 0, l = 0, r = 0, m = 0, ans_de = 0,
      ans_nu = 0;
  double ve = 0, ans = 1234567890, min = 0;
  scanf("%d %d %d", &x, &y, &n);
  ve = (double)x / y;
  if (y <= n) {
    solve(x, y);
    printf("%d/%d\n", x, y);
  } else {
    for (i = 1; i <= n; i++) {
      l = 0, r = (ve + 2) * i;
      while (l <= r) {
        m = (l + r) >> 1;
        if (double(m) / i < ve)
          l = m + 1;
        else
          r = m - 1;
      }
      if (l != 0) {
        min = fabs(ve - (double)l / i) < fabs(ve - (double)(l - 1) / i)
                  ? fabs(ve - (double)l / i)
                  : fabs(ve - (double)(l - 1) / i);
        j = fabs(ve - (double)l / i) < fabs(ve - (double)(l - 1) / i) ? l
                                                                      : (l - 1);
      } else
        min = fabs(ve - 0);
      if (fabs(ans) > fabs(min)) {
        ans = min;
        ans_de = i;
        ans_nu = j;
      }
    }
    printf("%d/%d\n", ans_nu, ans_de);
  }
  return 0;
}
