import java.io.*;
import java.util.Scanner;

class Clasa{
	public boolean prime(int a,int b){
		int d,aux;
		if(a<b){
			aux=a;
			a=b;
			b=aux;		
		}
		for(d=2;d<b;d++){
			if(a%d==0 && b%d==0){
				return false;
			}
		}
		if(a%b==0){
			return false;
		}
		return true;
	}
	
	public int functia_recursiva(int numar){
		int i,rezultat=0;
		if(numar==1){
			return 1;
		}
		else{
			for(i=numar-1;i>=1;i--){
				if(prime(numar,i)){
					rezultat+=2;
				}
			}
			return functia_recursiva(numar-1)+rezultat+2;
		}
	}
}

public class Main {

	public static void main(String [] args){
		try {
			Clasa c = new Clasa();
			Scanner s = new Scanner(new FileInputStream("fractii.in"));
			PrintWriter p = new PrintWriter("fractii.out");
			int n,raspuns;
			
			n=s.nextInt();
			

			p.print(c.functia_recursiva(10));
			
			
			s.close();
			p.close();
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

}