Ответ:

x = int(input())

hours = 0

minutes = 0

seconds = 0

seconds += x % 60

seconds = str(seconds)

minutes += (x // 60) % 60

hours += x // 60 // 60

minutes = str(minutes)

hours = str(hours)

if len(seconds) == 1:

seconds = '0'+seconds

if len(minutes) == 1:

minutes = '0'+minutes

print(hours + ':' + minutes + ':' + seconds)