import json

username_file = 'username.json'
try:
    with open(username_file) as file:
        print('Are you ' + json.load(file) + '?')
        check_username = input('Press Y if yes or N if no: ')
        if check_username == 'Y':
            print('Welcome back, ' + json.load(file))
        if check_username == 'N':
            username = input('Input your name: ')
            with open(username_file, 'w') as file:
                json.dump(username, file)
                print('See you next time!')
except FileNotFoundError:
    username = input('Input your name: ')
    with open(username_file, 'w') as file:
        json.dump(username, file)
        print('See you next time!')