import math


def pythagoras(x1, y1, x2, y2):
  """Calculates the distance between two points.

  :param x1: x coordinate
  :type x1: integer
  :param y1: y coordinate
  :type y1: integer
  :param x2: x coordinate
  :type x2: integer
  :param y2: y coordinate
  :type y2: integer
  :return: distance between the two points
  """
  x_diff = x1 - x2
  y_diff = y1 - y2
  distance = math.pow(x_diff,2) + math.pow(y_diff, 2)
  distance = math.sqrt(distance)
  return distance