#include <bits/stdc++.h>
using namespace std;
int a,b,sum,h,he;
const int N=1e8+5;
int a1[N];
int main()
{
    cin>>a>>b;
    for(int i=a;i<=b;i++)
    {
        if(i%2==1)
        {
            sum=i;
            while(sum)
            {
                he=he*10+sum%10;
                sum/=10;
            }
            if(i==he) a1[i]=2;
            he=0;   
        }
    }
    for(int i=2; i<=b; i++)
    {
        if(a1[i]==1) continue; //1为合数
        else if(a1[i]) cout<<i<<endl;
        for(int j=i; j<=b/i; j++) {a1[i*j]=1;}
    }
    return 0;
}