#include <stdio.h>
#include <iostream>
#include <algorithm>
using namespace std;
int IsPalindrome(int iNumber)
{
int temp=0;
int number = iNumber;
while(number){
temp=temp*10+(number%10);
number=number/10;
}
if(iNumber==temp)
return 1;
else
return 0;
}
int isPrime( int num )
{
if(num ==2|| num==3 )
return 1 ;
if(num %6!= 1&&num %6!= 5)
return 0 ;
int tmp =sqrtf(num);
for(int i= 5;i <=tmp; i+=6 )
if(num %i== 0||num %(i+ 2)==0 )
return 0 ;
return 1 ;
}
int main()
{
int a,b;
while(scanf("%d%d",&a,&b)!=EOF)
{
for(int i=1;i<=100000;i++)
if(IsPalindrome(i)&&isPrime(i)) cout<<i<<endl;
}
return 0;
}