class Time(object):
  def __init__(self, hour, minute, ampm):
    self.hour = hour
    self.minute = minute
    self.ampm = ampm  # midnight will be AM!!; ampm = 'AM' or 'PM'

  # This function returns the time 1 minute after time denoted by self
  def next(self):
    next = Time(0,0,'')
    if self.hour == 11 and self.minute == 59:
      if self.ampm == 'AM':
        h,m,a = 12,0,'PM'
      else:
        h,m,a = 12,0,'AM'
    elif self.hour == 12 and self.minute == 59:
      h,m,a = 1,0,self.ampm
    elif self.minute == 59:
      h,m,a = self.hour+1,0,self.ampm
    else:
      h,m,a = self.hour,self.minute+1,self.ampm
    return Time(h,m,a)

  # This function returns the time 1 minute before time denoted by self
  def previous(self):
    pass

  # This function returns the time nminutes seconds after time denoted by self
  def add(self,nminutes):
    t = Time(self.hour,self.minute,self.ampm)
    for i in range(nminutes):
      t = t.next()  
    return t

  # This function returns the time nminutes before time denoted by self
  def sub(self,nminutes):
    pass

  # This function returns number of minutes that have elapsed since midnight until time denoted by self
  def minutes_since_midnight(self):
    pass

  # This function returns True if time denoted by self is AFTER time denoted by t
  def after(self,t):
    pass

  # This function returns True if time denoted by self is EQUAL TO time denoted by t
  def equals(self,t):
    return ((self.minute == t.minute) and
            (self.hour == t.hour) and
            (self.ampm == t.ampm))

  # This function returns True if time denoted by self is BEFORE time denoted by t
  def before(self,t):
    pass

  # This function returns the number of seconds between time denoted by self and time denoted by t
  def minutes_between(self,t):
    pass

  # This function returns a string representation of the time denoted by self
  def __str__(self):
    def two_spaces(n):
      if n<10:
        return '0'+str(n)
      else:
        return str(n)
    return two_spaces(self.hour)+":"+two_spaces(self.minute)+self.ampm