輸入一個正整數判斷它是不是素數

from math import sqrt


def main():
    num = int(input('請輸入一個正整數: '))
    end = int(sqrt(num))
    is_prime = True
    for x in range(2, end + 1):
        if num % x == 0:
            is_prime = False
            break
    if is_prime and num != 1:
        print('%d是素數' % num)
    else
 
:
        print('%d不是素數' % num)


if __name__ == '__main__':
    main()