import datetime
N = input()
time_format = "%H:%M"
try:
    input_time = datetime.datetime.strptime(N, time_format)
except ValueError:
    print("無効な時刻形式です。")
else:
    time_difference = datetime.timedelta(minutes=5)
    new_time = input_time + time_difference
    print( new_time.strftime(time_format))