def password_generator():
    i = 0
    password = None
    user = input('wanna generate a new password : Y/N ')
    import random
    while user == 'Y' :
        while int(i) < 1:

            low_letter = random.choice('abcdefghijklmnopqrstuvwxyz')
            up_letter = random.choice('ABCDEFGHIJKLMNOPQRSTUVWXYZ')
            symbol = random.choice('`~!@#$%^&*()-_<,>./?{[}]')
            number = random.choice('1234567890')
            if password == None :

                password = low_letter + up_letter + symbol + number
                continue
            password = password + low_letter + up_letter + symbol + number

            i = i+1

        print("new password : " + password)
        user = input('wanna generate a new password : Y/N ')

        if user == 'N':
            print('end')

        if user != 'Y' and user != 'N':
            print('invalid input')
            user = input('wanna generate a new password : Y/N ')



password_generator()