#include <iostream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <set>
#include <vector>
#include <map>
#include <queue>
#include <stack>
#include <utility>
#include <string>
#include <cstring>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <limits>
#include <sstream>
#include <deque>
#include <bitset>
#include <complex>
#include <functional>
#include <memory>
#include <numeric>

using namespace std;

#define x first
#define y second

#define MAX 1000007

int PHI[MAX];

void compute() {
	for(int i = 2; i < MAX; i++)
		PHI[i] = i - 1;

	for(int i = 2; i < MAX; i++) {
		for(int j = i * 2; j < MAX; j += i)
			PHI[j] -= PHI[i];
	}
}

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

	int n;
	fin >> n;

	compute();

	long long sum = 0;
	for(int i = 0; i <= n; i++) {
		sum += PHI[i];
	}

	fout << 2LL * sum + 1LL;

	return 0;
}