#include<bits/stdc++.h>
using namespace	std;
int a,b;
string c,fc="";
set<int> p;
bool is_hui_wen(int num){
	string s1=to_string(num);
	string s2=s1;
	reverse(s1.begin(),s1.end());
	return s1==s2;
}
bool is_zhi_shu(int num){
	bool m=1;
	for(int i=2;i<sqrt(num-1);i++){
		if(num%i==0){
			m=0;
			break;
		}
	}
	return m;
}
int main(){
	cin>>a>>b;
	if(a==2)	cout<<"2\n"; 
	if(a%2==0)	a++;
	int max=0;
	b=min(b,9989900);
	for(int i=a;i<=b;i++){
		if(i%2==0) continue;
		if(is_hui_wen(i)&&is_zhi_shu(i)){
			cout<<i<<"\n";
		}
	}
	return 0;
}