#include <iostream>
#include <fstream>
using namespace std;
int euclid(int a, int b)
{
    int c;
    while (b) {
        c = a % b;
        a = b;
        b = c;
    }
    return a;
}
int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    int k=1,i,j;
    int C[100000], N, I, J;
    f>>N;
    for(I=1;I<=N;I++)
        C[I]=1;
    for(I=2;I<=N;I++)
        if(C[I]==1)
        for(J=2;J*I<=N;J++)
        C[I*J]=0;
    for(I=1;I<=N;I++)
        for(J=1;J<=N;J++)
        if(C[J]==1&&I!=J)
        k++;

    g<<k;



    return 0;
}