#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 998244353;

int main(){
    int N;
    cin >> N;
    vector<int> mu(N+1, 1);
    vector<bool> is(N+1, true);
    is[0] = false;
    is[1] = false;

    for (int n = 2; n <= N; n++){
        if (!is[n]) continue;
        for (int m = n; m <= N; m += n) mu[m] *= -1, is[m] = false;
        if ((ll)n*n > N) continue;
        for (int m = n*n; m <= N; m += n*n) mu[m] = 0;
    }

    cout << reduce(mu.begin(), mu.end())-1 << endl;
}