#include<stdio.h>
#include<math.h>
int main()
{
	int i=0,m,n,a[100000],k,t=0,s=0,h;
	scanf_s("%d%d", &m, &n);
	for (m; m < n; m++)
	{
		k = m;
		int b[10],x=0,y=0,z=0;
		for (k; k > 0; k /= 10)
		{
			b[x] = k% 10;
			x++;
		}
		for (x; x > 0; x--)
		{
			y = y + b[z] *(int) pow(10, x - 1);
			z++;
		}
		if (y == m&&(y/2==(y-1)/2))
		{
			a[t] = y;
			t++;
		}
	}
	for (s; s <= t; s++)
	{
		for (h = 2; h < a[s]; h++)
		{
			if (a[s]% h == 0)break;
		}
		if (a[s] == h)printf("%d\n", a[s]);
	}
	return 0;
}