output_description: Print the answer without units. Your output will be accepted when its absolute
  or relative error from the correct value is at most 10^{-9}.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      A B H M
attempt: import math
  
  
  class Watch:
      """
      This is a class to calculate angle and distance between two hands.
  
      Attributes:
          length_of_hour_hand(int): Length of the hour hand.
          length_of_minute_hand(int): Length of the minute hand.
          hours(int): Hours.
          minutes(int): Minutes.
      """
  
      def __init__(self, length_of_hour_hand, length_of_minute_hand, hours, minutes):
          """
          The constructor for Watch class.
  
          Attributes:
              length_of_hour_hand(int): Length of the hour hand.
              length_of_minute_hand(int): Length of the minute hand.
              hours(int): Hours.
              minutes(int): Minutes.
              angle_between_two_hands(float):
                  Angle between the hour hand and the minute one.
              distance_between_two_hands(float):
                  Distance between the tip of hour hand and
                  that of minute one.
          """
          self.length_of_hour_hand = length_of_hour_hand
          self.length_of_minute_hand = length_of_minute_hand
          self.hours = hours
          self.minutes = minutes
          self.angle_between_two_hands = None
          self.distance_between_two_hands = None
  
      def calculate_angle_between_two_hands(self):
          """
          Calculate angle between the hour hand and the minute one.
          """
  
          # degrees_of_hour_hand: float, radian
          degrees_of_hour_hand = (
              ((self.hours + self.minutes / 60.0) / 12.0) * 2.0 * math.pi
          )
          # degrees_of_minute_hand: float, radian
          degrees_of_minute_hand = (self.minutes / 60.0) * 2.0 * math.pi
  
          # angle_between_two_hands: float, radian
          angle_between_two_hands = degrees_of_hour_hand - degrees_of_minute_hand
  
          self.angle_between_two_hands = angle_between_two_hands
  
      def calculate_distance_between_two_hands(self):
          """
          Calculate distance between the tip of hour hand and
          that of minute hand.
          """
  
          self.distance_between_two_hands = math.sqrt(
              self.length_of_hour_hand**2
              + self.length_of_minute_hand**2
              - 2
              * self.length_of_hour_hand
              * self.length_of_minute_hand
              * math.cos(self.angle_between_two_hands)
          )
  
  
  # A, B, H, M: ints, A: the length of the hour hand,
  # B: the length of the minute hand, H: hours, M: minutes
  A, B, H, M = [int(s) for s in input().split(" ")]
  
  watch = Watch(A, B, H, M)
  watch.calculate_angle_between_two_hands()
  watch.calculate_distance_between_two_hands()
  print(watch.distance_between_two_hands)
  
problem_description: Statement
  
  Consider an analog clock whose hour and minute hands are A and B centimeters
  long, respectively.
  
  An endpoint of the hour hand and an endpoint of the minute hand are fixed at
  the same point, around which each hand rotates clockwise at constant angular
  velocity. It takes the hour and minute hands 12 hours and 1 hour to make one
  full rotation, respectively.
  
  At 0 o'clock, the two hands overlap each other. H hours and M minutes later,
  what is the distance in centimeters between the unfixed endpoints of the
  hands?
samples: [{"input": "3 4 9 0", "output": "5.00000000000000000000\n    \n\nThe two hands will be in the positions shown in the figure below, so the\nanswer is 5 centimeters.\n\n![The clock at <var>9</var>\no'clock](https://img.atcoder.jp/ghi/when_a_nameless_star_falls_into_the_sky.png)\n\n* * *"}, {"input": "3 4 10 40", "output": "4.56425719433005567605\n    \n\nThe two hands will be in the positions shown in the figure below. Note that\neach hand always rotates at constant angular velocity.\n\n![The clock at\n<var>10:40</var>](https://img.atcoder.jp/ghi/when_flower_petals_flutter.png)"}]