Sum seconds from book

first=int(input())
second=int(input())
third=int(input())
seconds=first+second+third
minutes=0

if 10<=seconds<=59:
  minutes=minutes
  seconds=seconds
elif seconds>59:
  minutes = seconds // 60
  seconds=seconds- minutes*60

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