01. Sum Seconds

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

total_sec_time = first_time + second_time + third_time

total_min = total_sec_time // 60
total_sec = total_sec_time % 60

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