#include <bits/stdc++.h>
using namespace std ;
int main (){
    int a, b ;
    scanf ("%d%d" , &a, &b) ;
    int w[999999], l = 1 ;
    if (a % 2 == 0)
        a++ ;
    for (int i=a; i<=b; i+=2){
        int t = i, q = 0 ;
        while (t != 0){
            q = q*10 + t%10 ;
            t = t/10 ;}
        if (i != q)
            continue ;
        bool flag = 1 ;
        for (int j=2; j<i; j++)
            if (i % j == 0){
                flag = 0 ;
                break ;}
        if (flag == 1){
            w[l] = i ;
            l++ ;}  }
    for (int i=1; i<=l-1; i++)
        printf ("%d\n" , w[i]) ;
    return 0 ;
}