小南解题--用筛法求之N内的素数。

'''zgn946

14:11 2022/5/9'''

def is_prime(num):  #素数判断

    if num==2 or num==3:

        return True

    if num%6!=1 and num%6!=5:

        return False

    for i in range(5,int(num**0.5)+1,6):

        if num%i==0 or num%(i+2)==0:

            return False

    return True

a=int(input())

for i in range(2,a+1):

    if is_prime(i):

        print(i)