01. Sum Seconds

first_time = int(input())
second_time = int(input())
third_time = int(input())
total_time_min = (first_time + second_time + third_time) // 60
total_time_sec = (first_time + second_time + third_time) % 60

if total_time_sec < 10:
    print(f"{total_time_min}:0{total_time_sec}")
else:
    print(f"{total_time_min}:{total_time_sec}")