#include <cstdio>
#define max_n 1000000 

using namespace std;

int n;
int sum[max_n];
long long sol;

void tera(){
    int i,j;
    for(i = 1;i<= n; i++)
    sum[i]=i-1;
    for(i = 2;i <=n; i ++ ){
          for(j = (i << 1); j <= n ; j+=i )sum[j]=sum[j] - sum[ i ];
          sol += sum[i];
    }
}

int main(void){
     freopen("fractii.in", "r", stdin);
     freopen("fractii.out", "w", stdout);
     scanf("%d ", &n);
     tera();
     sol= (sol<<1)|1;
     printf("%d\n",sol);   
}