text: from math import sqrt as msqrt
  from random import random
  
  def sqrt(x, eps):
      l = 0.
      r = max(1, float(x))
      while r - l > eps:
          m = (l + r) / 2
          if m ** 2 < x:
              l = m
          else:
              r = m
      return (l + r) / 2
  
  
  eps = 1e-8
  while True:
      x = random() * 100
      y1 = msqrt(x)
      y2 = sqrt(x, eps)
      if abs(y1 - y2) > eps:
          print(f'fail: {x:.9f}')
          exit(0)
      else:
          print('OK')
  