#include<bits/stdc++.h>
using namespace std;
int main()
{
    int i,j,s=0,a,b,t;
    cin>>a>>b;
    for(i=a;i<=b;i++)
	{
          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;
        }
    }
    s=0;
    }
    return 0;
}