#include<iostream>
using namespace std;
int main(){
	int a,b;
	cin>>a>>b;
	int i,j,t;
	for(i=a;i<=b;i++){
		int s=0;
		t=i;
		while(t!=0){
			s=s*10+t%10;
			t=t/10;
		}
		if(i==s){
			for(j=2;j*j<=i;j++){
				if(i%j==0){
					break;
				}
				
			}
			if(j*j>i){
					cout<<i<<endl;
				}
		}
	}
}