01. Sum Seconds

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

sum_sec = first_time + second_time + third_time

minutes = sum_sec // 60
seconds = sum_sec % 60

# print(f"{minutes}:{seconds:02}")

if seconds < 10:
    print(f"{minutes}:0{seconds}")
else:
    print(f"{minutes}:{seconds}")