messagetoencrypt = input("Please type the message you would like encrypted (and then press enter): ")

shift = input("Please type the shift you would like to apply (1-25): ")

if shift.isnumeric() == False:
  print("The shift is not numeric.")
  print("Exiting program now...")
  quit()


if int(shift) < 1 or int(shift) > 25:
  print("The shift is not within range.")
  quit("Exiting program now...")
  quit()

for i in range (0,int(shift)):
  encrypted = ""
  for letter in messagetoencrypt:
    if letter.lower() == "d":
      encrypted = encrypted + "e"
    elif letter.lower() == "e":
      encrypted = encrypted + "f"
    elif letter.lower() == "f":
      encrypted = encrypted + "g"
    elif letter.lower() == "g":
      encrypted = encrypted + "h"
    elif letter.lower() == "h":
      encrypted = encrypted + "i"
    elif letter.lower() == "i":
      encrypted = encrypted + "j"
    elif letter.lower() == "j":
      encrypted = encrypted + "k"
    elif letter.lower() == "k":
      encrypted = encrypted + "l"
    elif letter.lower() == "l":
      encrypted = encrypted + "m"
    elif letter.lower() == "m":
      encrypted = encrypted + "n"
    elif letter.lower() == "n":
      encrypted = encrypted + "o"
    elif letter.lower() == "o":
      encrypted = encrypted + "p"
    elif letter.lower() == "p":
      encrypted = encrypted + "q"
    elif letter.lower() == "q":
      encrypted = encrypted + "r"
    elif letter.lower() == "r":
      encrypted = encrypted + "s"
    elif letter.lower() == "s":
      encrypted = encrypted + "t"
    elif letter.lower() == "t":
      encrypted = encrypted + "u"
    elif letter.lower() == "u":
      encrypted = encrypted + "v"
    elif letter.lower() == "v":
      encrypted = encrypted + "w"
    elif letter.lower() == "w":
      encrypted = encrypted + "x"
    elif letter.lower() == "x":
      encrypted = encrypted + "y"
    elif letter.lower() == "y":
      encrypted = encrypted + "z"
    elif letter.lower() == "z":
      encrypted = encrypted + "a"
    elif letter.lower() == "a":
      encrypted = encrypted + "b"
    elif letter.lower() == "b":
      encrypted = encrypted + "c"
    elif letter.lower() == "c":
      encrypted = encrypted + "d"
    elif letter.lower() == " ":
      encrypted = encrypted + " "

    messagetoencrypt = encrypted
print ("Your encrypted message is: ", encrypted)