mport math

s,v = map(int,input().split())
t = math.ceil(s/v) + 10
n = t // 60
m = t % 60
hour = 7
minute = 60
if t >= 60:
    hour -= n
    minute -= m
    if m == 0:
        hour += 1
        print("0%d:00"%hour)
    elif m <= 50:
        print("0%d:%d"%(hour,minute))
    elif m > 50:
        print("0%d:0%d"%(hour,minute))

else:
    minute -= m
    if m <= 50:
        print("0%d:%d"%(hour,minute))

    elif m > 50:
        print("0%d:0%d"%(hour,minute))