#include<stdio.h>
#include<math.h>
int prime(int x)
{
	if (x == 1)
	{
		return 0;
	}
	if (x == 2 || x == 3)
		return 1;
	for (int i = 2; i <= sqrt(x); i++)
	{
		if (x % i == 0)
			return 0;
	}
	return 1;
}
int hw_prime(int x)
{
	if ((x >= 1000 && x <= 9999) || (x >= 100000 && x <= 999999))
		return 0;
	int i=1,m=0;
	int a[20];
	do
	{
		a[i] = x % 10;
		x /= 10;
		i++;
	} while (x!=0);
	for (int j = 1; j <= (i - 1)/2; j++)
	{
		if (a[j] != a[i - j])
			return 0;
	}
	return 1;
}
int main()
{
	int a, b;
	scanf("%d%d", &a, &b);
	if(a%2==0)
	{
		a++;
		for (int i = a; i <= b; i += 2)
		{

			if (prime(i) && hw_prime(i))
			{
				printf("%d\n", i);
			}
		}
	}
	else
	{
		for (int i = a; i <= b; i += 2)
		{

			if (prime(i) && hw_prime(i))
			{
				printf("%d\n", i);
			}
		}
	}
	return 0;
}