output_description: Print $h$, $m$ and $s$ separated by ':'. You do not need to put '0' for a
  value, which consists of a digit.
input_description: An integer $S$ is given in a line.
attempt: s = int(input())
  sec = int(s % 60)
  hm = int(s // 60)
  if hm == 0:
      print("::" + str(sec))
  else:
      m = int(hm % 60)
      h = int(hm // 60)
      print(str(h) + ":" + str(m) + ":" + str(sec))
  
problem_description: Watch
  
  Write a program which reads an integer $S$ [second] and converts it to $h:m:s$
  where $h$, $m$, $s$ denote hours, minutes (less than 60) and seconds (less
  than 60) respectively.
samples: [{"input": "46979", "output": "13:2:59"}]