class Time:
    def __init__(self, hour, minute):
        self.hour = hour
        self.minute = minute

    def addminutes(self,dminutes):
        self.minute += dminutes
        self.hour += int(self.minute / 60)
        self.minute = self.minute % 60

    def __str__(self):
        return "%02d:%02d" % (self.hour,self.minute)


t = Time(7,30)

for i in range(8):
    print("%d.DS: %s" % (i+1,str(t)))
    t.addminutes(90+20)