#include<bits/stdc++.h>
using namespace std;
int ans=0;
bool P(int n) {
    if (n<=1) return 0;
    if (n<=3) return 1;
    if (n%2==0 || n%3==0) return 0;
    for (int i=5;i*i<=n;i+=6){
        if (n%i==0 || n%(i+2)==0) return 0;
    }
    return 1;
}
bool p(int n){
    string s=to_string(n);
    string rev=s;
    reverse(rev.begin(),rev.end());
    return s==rev;
}
void f(int a,int b) {
    for (int i=5;i<=11;i+=2){
        if (i>=a && i<=b) cout<<i<<'\n';
    }
    for (int i=1;i<=9;i+=2){
        for (int j=0;j<=9;++j){
            int num=i*100+j*10+i;
            if (num>=a && num<=b && P(num)){
                cout<<num<<'\n';
            }
        }
    }
    for (int i=1;i<=9;i+=2){
        for (int j=0;j<=9;++j){
            for (int k=0;k<=9;++k){
                int num=i*10000+j*1000+k*100+j*10+i;
                if (num>=a && num<=b && P(num)){
                    cout<<num<<'\n';
                }
            }
        }
    }
    for (int i=1;i<=9;i+=2){
        for (int j=0;j<=9;++j){
            for (int k=0;k<=9;++k){
                for (int l=0;l<=9;++l){
                    int num=i*1000000+j*100000+k*10000+l*1000+k*100+j*10+i;
                    if (num>=a && num<=b && P(num)){
                        cout<<num<<'\n';
                    }
                }
            }
        }
    }
}
int main(){
    int a,b;
    cin>>a>>b;
    if (a%2==0) ++a;
    f(a,b);
    return 0;
}