#include<iostream>
#include<cmath>
int sushu(int i)
{
	int flog=0,m;
	for(m=2;m<=sqrt(i);m++)
	{
		if(i%m==0)
		{
			flog=1;
			break;
		}
		if(flog==0&&i!=1)
		return 1;
		else
		return 0;
	}
}
int huiwen(int i)
{
	int sum=0,a=i;
	while(i)
	{
		sum=sum*10+i%10;
		i/=10;
	}
	if(a==sum)
	return 1;
	else
	return 0;
}
using namespace std;

int main()
{
int m,i,sum=0;
cin>>m;
for(i=pow(10,m);i<=pow(10,m+1)-1;i++)
{
if(sushu(i)&&huiwen(i))	
sum++;
}
cout<<sum;
}