#include<iostream>
using namespace std;
bool solve(int x)
{
if(x%2 == 0&& x % 3) return true;
else return false;
}
int main()
{
int n;
int ans=0;
cin>>n;
for(int i=1;i<=n;i++)
{
if(solve(i)) ans++;
}
cout<<ans;
return 0;
}