# coding=utf-8
# 过滤反转
# 回数
def is_palindrome(n):
    return str(n) == str(n)[::-1]


output = filter(is_palindrome, range(1, 1000))
#print(list(output))


# 计算
def is_odd(n):
    return 1 == n % 2


L = range(100)
#print(list(filter(is_odd, L)))


def not_empty(s):
    return s and s.strip()


#print(list(filter(not_empty, ['A', '', 'B', None, 'C', '  '])))


def main():
    for n in primes():
        if n < 1000:
            print(n)
        else:
            break

def _odd_iter():
    n = 1
    while True:
        n = n + 2
        yield n

def _not_divisible(n):
    return lambda x: x % n > 0

def primes():
    yield 2
    it = _odd_iter()
    while True:
        n = next(it)
        yield n
        it = filter(_not_divisible(n), it)

if __name__ == '__main__':
    main()