old_contents: #!/usr/bin/python3.6
  """Jerod Gawne, 2017-10-04
  
  Mutations
  
  https://www.hackerrank.com/challenges/python-mutations/
  
  Editorial:
   -
  """
  
  
  def mutate_string(string, position, character):
      """
      Changes string at position to character
  
      :param string:
      :param position:
      :param character:
      :return:
      """
      return string[:position] + character + string[position + 1:]
  
  
  def main():
      """
      Main/Tests
      """
      s = input()
      i, c = input().split()
      s_new = mutate_string(s, int(i), c)
      print(s_new)
  
  
  if __name__ == '__main__':
      try:
          main()
      except Exception:
          import sys
          import traceback
  
          print(traceback.print_exception(*sys.exc_info()))
  
new_contents: #!/usr/bin/python3.6
  """Jerod Gawne, 2017-10-04
  
  Mutations
  
  https://www.hackerrank.com/challenges/python-mutations/
  
  Editorial:
   -
  """
  
  
  def mutate_string(string, position, character):
      """
      Changes string at position to character
  
      :param string:
      :param position:
      :param character:
      :return:
      """
      return string[:position] + character + string[position + 1:]
  
  
  def mutate_string2(string, position, character):
      """
      Changes string at position to character
  
      :param string:
      :param position:
      :param character:
      :return:
      """
      return ''.join([character if i == position else string[i] for i in range(len(string))])
  
  
  def main():
      """
      Main/Tests
      """
      s = input()
      i, c = input().split()
      s_new = mutate_string(s, int(i), c)
      print(s_new)
  
  
  if __name__ == '__main__':
      try:
          main()
      except Exception:
          import sys
          import traceback
  
          print(traceback.print_exception(*sys.exc_info()))
  
subject: add alternate method