def caesar_encrypt(str, n):
  res = list(str)
  str_char_set = set(str)
  for i in str_char_set:
    if i.isalpha():
      new_char = ''
      if i.islower():
        new_char = chr(ord('a') + (((ord(i) - ord('a')) + n) % 26))
      else:
        new_char = chr(ord('A') + (((ord(i) - ord('A')) + n) % 26))
      for j in find(str, i):
        res[j] = new_char
  return ''.join(res)

def find(s, ch):
    return [i for i, ltr in enumerate(s) if ltr == ch]