Vigenere cipher

#############################################################
############ Vigenere Cipher by InjectioN ###################
#############################################################
 
count = 0
Output = []
Encrypted = []
KeyList = []
StringList = []
Alphabet = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"]
print("What would you like to do:")
print("Options:")
print("1 - Encrypt")
print("2 - Decrypt")
 
print()
 
while 1==1:
 
    Option = int(input("Option = " ))
    Key = input("Please enter the key you'd like to use: ")
    String = input("Please enter the String you'd like to encrypt/decrypt: ")
    String = String.replace(' ', '')
 
    KeyLength = len(Key)
    StringLength = len(String)
 
    OverLap = StringLength % KeyLength
    LeftOvers = Key[:OverLap]
    Random = StringLength-OverLap
    Random = StringLength/KeyLength
    Key = (int(Random)*Key)+LeftOvers
 
    for i in Key:
        Number = Alphabet.index(i.upper())
        KeyList.append(Number)
 
    for i in String:
        Number = Alphabet.index(i.upper())
        StringList.append(Number)
 
    i = 0
 
    if(Option == 1):
        while count < StringLength:
            Encrypted.append((StringList[i]+KeyList[i])%26)
            count += 1
            i += 1
        for N in Encrypted:
            Output.append(Alphabet[N])
 
    elif(Option == 2):
        while count < StringLength:
            Encrypted.append((StringList[i]-KeyList[i])%26)
            count += 1
            i += 1
        for N in Encrypted:
            Output.append(Alphabet[N])
 
 
    String = ''.join(Output)
    print()
    print('OUTPUT::')
    print()
    print(String)
    print()
    print()