import math

def is_huiwen(n):
    n = str(n)
    if n == n[::-1]:
        return True
    return False


def is_prime(n):
    if n <= 1:
        return False
    if n == 2 or n == 3:
        return True
    if n % 2 == 0 or n % 3 == 0:
        return False

    for i in range(5, int(math.sqrt(n)) + 1, 6):
        if n % i == 0 or n % (i + 2) == 0:
            return False

    return True

a, b = map(int, input().split())
ret = []
for i in range(a, b + 1):
    if is_huiwen(i) and is_prime(i):
        ret.append(i)

for i in ret:
    print(i)