Binary Search

#include <cstdio>
#include <algorithm>
using namespace std;

int main() {
  long long w, h, n, lo = -1, hi, mi;
  scanf("%lld%lld%lld", &w, &h, &n);
  hi = max(w * n, h * n);
  while (lo + 1 != hi) {
    mi = (lo + hi) / 2;
    ((mi / w) * (mi / h) >= n ? hi : lo) = mi;
  }
  printf("%lld\n", hi);
  return 0;
}