text: 
  def mutate_string(string, position, character):
      lst = list(string)
      lst[position] = character
      string = ''.join(lst)
      return string
  
  if __name__ == '__main__':
      s = raw_input()
      i, c = raw_input().split()
      s_new = mutate_string(s, int(i), c)
      print s_new
      
  '''
  Input:
  hellootherside
  5 0
  
  Output:
  hello0therside
  '''
  