current_users=['Niuniu','Niumei','GURR','LOLO']
new_users=['GurR','Niu Ke Le','LoLo','Tuo Rui Chi']
current_users_1=[]
for user in current_users:
    user=user.lower()
    current_users_1.append(user)
for name in new_users:   
    name1=name.lower()
    if name1 in current_users_1:
        print(f"The user name {name} has already been registered! Please change it and try again!")
    else:
        print(f"Congratulations, the user name {name} is available!")