Basic Python Message Encryption System

print("A = 1, B = 2, C = 3, D = 4, E = 5, F = 6, G = 7, H = 8, I = 9, J = 10, K = 11, L = 12, M = 13, N = 14, O = 15, P = 16, Q = 17, R = 18, S = 19, T = 20, U = 21, V = 22, W = 23, X = 24, Y = 25, Z = 26")
print("Enter your message!")
input()
#make as many inputs as you want, you can only do one letter per input or the encryption won't work
if input == "A" or "a":
    print("1")
if input == "B" or "b":
    print("2")
if input == "C" or "c":
    print("3")
if input == "D" or "d":
    print("4")
if input == "E" or "e":
    print("5")
if input == "F" or "f":
    print("6")
if input == "G" or "g":
    print("7")
if input == "H" or "h":
    print("8")
if input == "I" or "i":
    print("9")
if input == "J" or "j":
    print("10")
if input == "K" or "k":
    print("11")
if input == "L" or "l":
    print("12")
if input == "M" or "m":
    print("13")
if input == "N" or "n":
    print("14")
if input == "O" or "o":
    print("15")
if input == "P" or "p":
    print("16")
if input == "Q" or "q":
    print("17")
if input == "R" or "r":
    print("18")
if input == "S" or "s":
    print("19")
if input == "T" or "t":
    print("20")
if input == "U" or "u"
    print("21")
if input == "V" or "v"
    print("22")
if input == "W" or "w"
    print("23")
if input == "X" or "x"
    print("24")
if input == "Y" or "y"
    print("25")
if input == "Z" or "z"
    print("26")
#decryption script coming out soon!