input_text = "Hello World!"
output_text = ""

from_map = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
to_map   = "NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm"

rot_char = lambda character: to_map[from_map.find(character)] if from_map.find(character) > -1 else character
output_text = ''.join(rot_char(character) for character in input_text)

print(output_text)