#include <iostream>
using namespace std;
int a,b;
char c[10+2];
int ans;
bool Pali_Bool;
bool Prime_Bool;
bool Prime_Bool_Function(int Num)
{
	if (Num == 1)
	{
		return false;
	}
	for (int j = 2;j <= Num;j++)
	{
		if (Num%j == 0 && Num != j)
		{
			return true;	
		}
	}
	return false;
}
int main()
{
	cin >> a >> b;
	for (int i = a;i <= b;i++)
	{
		Pali_Bool = true;
		ans = 0;
		int i_num = i;
		while (i_num > 0)
		{
			ans++;
			c[ans] = (i_num % 10) + '0';
			i_num /= 10;
		}
		for (int i = 1;i <= ans;i++)
		{
			if (c[i] != c[ans + 1 - i])
			{
				Pali_Bool = false;
				break;
			}
		}
		if (Pali_Bool)
		{
			if (Prime_Bool_Function(i) == false)
			{
				cout << i << endl;
			}
		}
	}
	return 0;
}