Homework for school not working spams or just dont work

name = input ("Enter name :")
gender = input("are you a m/M or a f/F:")
while gender != 'M' or gender != 'm' or gender != 'f' or gender != 'F':
    if gender in ['M', 'm']:
        print("Hello Mr",name,",")
if gender in ['F', 'f']:
    print("Hello Miss",name,",")

cant seem to fix it if I do M or m it spams Hello Mr (name) tried it with female just dont do anything