#include<iostream>
#include<fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int i, j, s = 0, n;
int divizor = 2;
int cmmdc(int a, int b) {
	while (divizor <= b) {
		if ((a % divizor == 0) && (b % divizor == 0)) {
			s = divizor;
		}
		divizor++;
	}
	if (s == 0) {
		return 1;
	}
	else {
		return 0;
	}
}
int fractii(int n) {
	while (i <= n && j <= n) {
		if ((i != 1 && j != 1) && (cmmdc(i, j) == 0)) {
			s = s;
		}
		else {
			s++;
		}
	}
	return s;


	/*for (i = 1; i <= n; i++) {
		for (j = 1; j <= n; j++) {
			if ((i != 1 && j != 1) && (cmmdc(i,j)==0)) {
				s++;
			}
        }
	}
	return s;*/
}
int main() {
	fin >> n;
	fout << fractii(n);
	
}