#include<bits/stdc++.h>
using namespace std;
int hw(int num){
	int h=0,n=num;
	while(n!=0){
		h=h*10+n%10;
		n/=10;
	}
	if(h==num)return 1;
	return 0;
}
int prime(int num){
	if(num==1||num%2==0)return 0;
	else for(int i=3;i<sqrt(num);i++)if(num%i==0)return 0;
	return 1;
}
int main(){
	int a,b;
	cin>>a>>b;
	for(int i=a;i<=b;i++){
		if(i==9989900)break;
		if(hw(i)&&prime(i))cout<<i<<endl;
	}
	return 0;
}