#include <iostream>

using namespace std;

bool check(double x) {
  return true;
}

int main() {
  double l = 0;
  double r = 1e9;

  for (int i = 0; i < 64; ++i) {
    double mid = (l + r) / 2;

    if (check(mid)) {
      r = mid;
    } else {
      l = mid;
    }
  }
}