#include <bits/stdc++.h>
using namespace std;
long long int gcd(long long int a, long long int b) {
  long long int r = a % b;
  while (1) {
    if (r == 0) {
      return b;
    } else {
      a = b;
      b = r;
      r = a % b;
    }
  }
}
int main() {
  long long int x, y;
  cin >> x >> y;
  long long int r = gcd(x, y);
  x = x / r;
  y = y / r;
  long long int n;
  int mm;
  cin >> n;
  if (n >= y) {
    cout << x << "/" << y << endl;
  } else {
    long long int i;
    long long int mina = 1;
    long long int minb = 1;
    long long int di;
    long long int j;
    long long int diff;
    long long int p, q;
    for (i = 1; i <= n; i++) {
      di = abs((x * i) / y);
      mm = 0;
      if (mm < di - 5) {
        mm = di - 5;
      }
      for (j = mm; j <= di + 1; j++) {
        p = abs(((x * i) - (y * j)) * (minb));
        q = abs(((x * minb) - (y * mina)) * (i));
        if (p < q) {
          mina = j;
          minb = i;
        } else if (p == q) {
          if (minb > i) {
            minb = i;
          } else if (minb == i) {
            if (mina > j) {
              mina = j;
            }
          }
        }
      }
    }
    r = gcd(mina, minb);
    cout << mina / r << "/" << minb << endl;
  }
  return 0;
}
