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

def is_prime(num):

    if num<2:
       return False
    for i in range(2,int(num**0.5)+1):
       if num%i==0:
           return False
    return True

def huiwen(num):

      return str(num)==str(num)[::-1]

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

     if is_prime(i) and huiwen(i):
         print(i)