#include <fstream>

using namespace std;

long long gcd(long long a, long long b) {
    if (b == 0)
        return (a == 1) ? 0 : a;
    return gcd(b, a % b);
}

int main() {
    ifstream fi("fractii.in");
    ofstream fo("fractii.out");

    long long n;
    fi >> n;

    long long ans = n * n - (n - 1);
    for (long long i = 2; i * i <= n; i++)
        for (long long j = i * i; j <= n; j ++)
            if (gcd(i, j) != 1)
                ans -= 2;

    fo << ans;

    return 0;
}