def factorial(n):
    if n<0:
        raise ValueError('n should be positive')
    elif not isinstance(n,int):
        raise TypeError('n should be integer')

    if n == 1:
        return 1
    else:
        return n*factorial(n-1)


def main():
    print 'This program finds n!'

    choice = 'y'

    while choice == 'y' or choice == 'yes':
        n=input('please, input n:')

        print n, type(n)

        F=factorial(n)

        print "%d! = %d"%(n,F)

        choice = raw_input('Would you like to continue? (Y or Yes):')
        choice=choice.lower()

    print 'Have a good day!'

main()