import math
from typing import TextIO


a,b = input().split()
a,b = int(a),int(b)

#代 码 重 构
looper = [11]
k = len(str(b))+1
siz = k//2

#回文数
for i in range(10**siz):
    i = str(i)
    inv = i[::-1]
    final = i[:-1]+inv
    final = int(final)
    looper.append(final)


#欧拉筛
o = list(range(3,10**(k-1),2))
pri = [2]
while(o):
    flag = o[0]
    pri.append(flag)
    for x in o:
        if x%flag == 0: o.remove(x)

for i in range(a,b+1):
    if i in pri and i in looper: print(i)