///Ciurul lui Eratosthenes
#include <stdio.h>
#include <stdlib.h>
#define MAX 2000000
int n, nr ;
int Prime_intre_ele( int a, int b){
    int r;
    while(b!=0){
        r=a%b;
        a=b;
        b=r;
    }
    if(a==1)
       return 1;
    else return 0;
}
char ciur[MAX];
int main()
{
    freopen("fractii.in", "r", stdin);
    freopen("fractii.out", "w", stdout);
    int i, j, nr = 0;
    scanf("%d",&n);
    /**
    for ( i = 2; i*i <= n; i++){
        if( ciur[i] == 0)
            for(j= i*i; j<= n; j +=i)
                ciur[j] = i;
    }*/
    nr=n;
    for( i = 2; i<= n; i++)
        for( j = 1; j <= n; j++)
            if(Prime_intre_ele(i,j)==1)
                nr++;
    printf("%d ",nr);
    return 0;
}