#include <bits/stdc++.h>
using namespace std;
int n,m;
int pdhw(int j)
{
    int sum=0,k=j;
    while(j!=0)
        sum=sum*10+(j%10),j/=10;
    return sum==k;
}
int pdzs(int j)
{
    if(j==0||j==1)return 0;
    else if(j%2==0)return 0;
    int h=3;
    while(h*h<=j){
        if(j%h==0)
            return 0;
        else h+=2;}
    return 1;
}
int main()
{
    cin>>n>>m;
    for(int i=n;i<=m;i++)
        if(pdhw(i)&&pdzs(i))
            cout<<i<<endl;
    return 0;
}