output_description: Print the lexicographically smallest string after performing exactly K
  operations on s.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      s
      K
attempt: alphabet = 'abcdefghijklmnopqrstuvwxyz'
  s = input()
  K = int(input())
  ans = ''
  for i in range(len(s) - 1):
      s_i = alphabet.index(s[i])
      elif (26 - s_i < K) & (s_i != 0):
          K -= 26 - s_i
          s_i = 0
      ans += alphabet[s_i]
  s_i = (alphabet.index(s[-1]) + K) % 26
  ans += alphabet[s_i]
  print(ans)
  
problem_description: Statement
  
  Mr. Takahashi has a string s consisting of lowercase English letters. He
  repeats the following operation on s exactly K times.
  
    * Choose an arbitrary letter on s and change that letter to the next alphabet. Note that the next letter of `z` is `a`.
  
  For example, if you perform an operation for the second letter on `aaz`, `aaz`
  becomes `abz`. If you then perform an operation for the third letter on `abz`,
  `abz` becomes `aba`.
  
  Mr. Takahashi wants to have the lexicographically smallest string after
  performing exactly K operations on s. Find the such string.
samples: [{"input": "xyz\n    4", "output": "aya\n    \n\nFor example, you can perform the following operations: `xyz`, `yyz`, `zyz`,\n`ayz`, `aya`.\n\n* * *"}, {"input": "a\n    25", "output": "z\n    \n\nYou have to perform exactly K operations.\n\n* * *"}, {"input": "codefestival\n    100", "output": "aaaafeaaivap"}]