#include <fstream>

using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int i,j,n,nr,k;
bool a[10001][10001];
int main()
{
fin>>n;

for(i=1;i<=n;i++)
{
    for(j=1;j<=n;j++)
    {
        if(a[i][j]==0)
        {   nr++;
            for(k=2;k*j<=n&&k*i<=n;k++)
            {
                a[i*k][j*k]=1;
            }
        }
    }
}
fout<<nr;

    return 0;
}