#include<bits/stdc++.h>
using namespace std;

bool zhishu(int n)
{
	if (n < 2) return 0;
	for (int i = 2; i * i <= n; ++i)
	{
		if (n % i == 0) return 0;
	}
	return 1;
}
bool fanzhuan(int n)
{
	int a = 0;
	int b = n;
	while (n != 0)
	{
		a = a * 10 + n % 10;
		n /= 10;
	}
	if (b != a) return 0;
	return 1;
}
int main()
{
	int a, b,flag=0;
	cin >> a >> b;
	for (int i = a; i < b; i++)
	{
		if (zhishu(i) && fanzhuan(i))
		{
			cout << i << endl;
		}
	}
	return 0;
}