Sum Seconds

# 1. Read input (seconds)
first_time = int(input())
second_time = int(input())
third_time = int(input())

# 2. Sum input

sum_seconds = first_time + second_time + third_time

minutes = sum_seconds // 60
seconds = sum_seconds % 60

# 4. Check if seconds < 10 -> leading zero
#       a: print minutes + :0 + seconds
#       b: print minutes + :second

if seconds < 10:
    print(str(minutes) + ':0' + str(seconds))
else:
    print(str(minutes) + ':' + str(seconds))