#include <stdio.h>
int zhi(int a)
{
	int re=0;
	for(int i=2;i<a;i++){
		if(a%i==0){
			re=1;
		}
	}
	return re;
}
int hui(int a)
{
	int n=a;
	int intages=0,intall=0;
	int re=1;
	while(n!=0){
		intages=n%10;
		intall=intall*10+intages;
		n/=10;
	}
	if(intall==a){
		re=0;
	}
	return re;
	
}


int main()
{
	int a,b;
	scanf("%d%d",&a,&b);
	for(int i=a;i<=b;i++){
		if(zhi(i)==0){
			if(hui(i)==0){
				printf("%d\n",i);
			}
		}
	}
	
	return 0;
}