users = {'adam' : 'Test123', 'alice' : 'Test321'}
status = ""
status = input("If you have an account, type YES, NO to create a new user, QUIT to exit: ")

while status != 'QUIT':

    if status == "YES":
        u_name = input("Please provide your username: ")
        u_pwd = input("Please provide your password: ")

        if users.get(u_name) == u_pwd:
            print("Access granted!")
            break

        else:
            print("User doesn't exist or password error! You have 2 more attempts!")

    elif status == "NO":
        print("nYou're about to create a new user on my very first app. Thank you!")
        new_u_name = input("Please select a name for your account!")
        new_u_pwd  = input("Please select a password for your account!")
        users[new_u_name] = new_u_pwd
        print("Thank you " + new_u_name + " for taking the risk.")

    elif status == "QUIT":
        print("Smart choice lol. Please come back in few months")