import math
s,v = map(int,input().split()) # get distance and velocity
time_sum = math.ceil(s/v) + 10 # get total time
# print(time_sum)
hour_sub = time_sum // 60
minute_sub = time_sum % 60
ans_hour = 0
ans_minute = 60 - minute_sub
if hour_sub <= 8:
    ans_hour = 7 - hour_sub
    print(f'0{ans_hour}:{ans_minute}')
elif hour_sub > 8:
    ans_hour = 24 - hour_sub
    if ans_hour > 10:
        print(f'{ans_hour}:{ans_minute}')
    else:
        print(f'0{ans_hour}:{ans_minute}')