Caesar encoding

caesar.py

alph = [
	"ABCDEFGHIJKLMNOPQRSTUVWXYZ",
	"abcdefghijklmopqrstuvwxyz",
]

text = input("Enter the text\n>>")

shift = input("Enter the shift\n>>")

try:
	shift = int(shift)

except ValueError:
	print("Shift must be a number!")


else:
	encoded = ""

	for i in text:
		if  i.isalpha():
			if i.isupper():
				index = alph[0].index(i)
				index +=shift

				while index>26:
					index -= 26

				encoded += alph[0][index]

			else:
				index = alph[1].index(i)
				index += shift

				while index>26:
					index -= 26
				encoded += alph[1][index]

		else:
			encoded+=i

	print(encoded)