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


def ishuiwen(n):
    checklist = list(str(n))
    for i in range(len(checklist)):
        if checklist[i] != checklist[len(checklist) - 1 - i]:
            return False
    return True


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

anslist = []
for i in range(a, b + 1): 
    if isprime(i) and ishuiwen(i):
        anslist.append(i)

for i in anslist:
    print(i)