01. Sum Seconds

first_time = int(input())
second_time = int(input())
third_time = int(input())

sum_all_sec = first_time + second_time + third_time

total_minutes = sum_all_sec // 60
total_sec = sum_all_sec % 60

if total_sec < 10:
    print(f"{total_minutes}:0{total_sec}")
else:
    print(f"{total_minutes}:{total_sec}")