#include<stdio.h>
#define N 10000000
int a[N];

void fun()
{
    int i,j;
    for(i=2;i <= N;i++)
    {
        if(a[i] == 0)
        for(j=2*i;j <= N;j+=i)
            a[j] = 1;
    }
}

int main()
{
    fun();
    int i,j;
    int x,y;
    scanf("%d%d",&x,&y);
    if(y>N)
        y = 99999999;
    for(i=x;i <= y;i++)
    {
        if(a[i]==0)
        {
            j =i;
            int num=0;
            while(j)
            {
                num = num*10+j%10;
                j /= 10;
            }
            if(num == i)
            {
                printf("%d\n",i);
            }
        }
        else continue;
    }
    return 0;
}