class Duration:
    def __init__(self, minutes, seconds):
        self.minutes = minutes
        self.seconds = seconds
        self.total_seconds = self.minutes*60 + self.seconds

    def get_minutes(self):
        return self.total_seconds // 60

    def get_seconds(self):
        return self.total_seconds % 60

    def __str__(self):
        if self.get_seconds() < 10:
            a = "0" + str(self.get_seconds())
        else:
            a = str(self.get_seconds())
        if self.get_minutes() < 10:
            b = "0" + str(self.get_minutes())
        else:
            b = str(self.get_minutes())
        return b + ":" + a

    def __add__(self, new_duration):
        return Duration(self.minutes + new_duration.minutes, self.seconds + new_duration.seconds)