#class Interval:
#  def __init__(self, start, end):
#    self.start = start
#    self.end = end

#  def print_interval(self):
#    print("[" + str(self.start) + ", " + str(self.end) + "]", end='')


class Solution:
  def canAttendAllAppointments(self, intervals):
    
    def do_overlap(a, b):
      return b.start < a.end
    
    # sort the intervals first to compare the overlapping intervals
    intervals.sort(key = lambda x: x.start)
    
    for i in range(1, len(intervals)):
      # check the interval and the previous interval for overlapping 
      if do_overlap(intervals[i - 1], intervals[i]):
        return False
    
    return True