time

time_first = int(input())
time_second = int(input())
time_third = int(input())
total_time = time_first + time_second + time_third
time_minute = total_time // 60
time_sec = total_time - time_minute
time_sec_time = (total_time % 60)

if time_sec_time <= 9:
    print(f"{time_minute}:0{time_sec_time}")
else:
    print(f"{time_minute}:{time_sec_time}")