def is_prime(num):
flag = True
if num < 2:
flag = False
if num % 2 == 1:
for i in range(2,int(num**0.5)+1):
if num % i == 0:
flag = False
break
else:
flag = False
if num == 2:
flag = True
return flag
def is_huiwen(num):
num = str(num)
if num == num[::-1]:
return True
else:
return False
a,b = map(int,input().split())
for i in range(a,b+1):
if is_huiwen(i):
if is_prime(i):
print(i)
