#include<fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int n,v[2000005],nr(0),j,i;
int main()
{
	f>>n;
	for(i=0;i<n;i++)
		v[i]=i;
	p=2;
	while(p*p<n)
	{
		for(j=2;j<=n;j++)
			if(v[j-2]%j!=0)
				while(v[j-2]%j!=0)
				v[j]=j;