#include <iostream>
#include <fstream>
#include <math.h>
using namespace std;

ifstream fin("fractii.in");
ofstream fout("fractii.out");

int prim(int n)
{
    for (unsigned i = 2; i < sqrt(n); i++)
        if (n % i == 0)
            return 0;
    return 1;
}

int main()
{
    int N, P, Q, nr = 0, k;
    fin>>N;
    for (P = 1; P <= N; P++)
        for (Q = 1; Q <= N; Q++)
            {
                if (P > Q)
                    if (prim(Q))
                        if(prim(P))
                            nr++;
                else
                    if (prim(P))
                        if(prim(Q))
                            nr++;
            }
    fout<<nr;
    fin.close();
    fout.close();
    return 0;
}