#include <bits/stdc++.h>

using namespace std;

int n;
int64_t solution = 1;

void read() {
    ifstream fin("fractii.in");

    fin >> n;

    fin.close();
}

void solve() {
    vector <int> dp(n + 1);
    iota(dp.begin(), dp.end(), -1);

    for (int i = 2; i <= n; ++i) {
        solution += 2 * dp[i];
        for (int j = 2 * i; j <= n; j += i)
            dp[j] -= dp[i];
    }
}

void write() {
    ofstream fout("fractii.out");

    fout << solution;

    fout.close();
}

int main() {
    read();
    solve();
    write();
    return 0;
}