How do I check if a user has inputed a certain word

How do I check if a user has inputed a certain word

I have a variable with the value of input("") and I want it to check if
the input has a certain word in it.
Code:
print("John: Hello!")
print('')
talkingToJohn = ''
while talkingToJohn != "Bye":
talkingToJohn = input("")