#include<bits/stdc++.h>
using namespace std;
int cnt;
bool a[100000001]={1,1};
int n,m;   
int b[100000001];
int fun(int ans){
    int t=ans,sum=0;
    while(t!=0){
    	sum=sum*10+t%10;
    	t/=10;
	} 
	if(sum==ans)return 0;
	else return 1;
}
void oula(){
	for(int i=2;i<=m;i++){
		if(a[i]==0)b[++cnt]=i;
		for(int j=1;j<=cnt;j++){
			if(i*b[j]>m)break;
			a[i*b[j]]=1;
			if(i%b[j]==0)break;
		}
	}
}
int main(){
    cin>>n>>m;
    oula();
    if(n%2==0)n++;
    for(int i=n;i<=m;i+=2){
        if(fun(i)==0&&a[i]==0)cout<<i<<endl;
    }
    return 0;
}