#include    <stdio.h>
#define MAX 1000002
FILE * in = fopen("fractii.in","r");
FILE * out = fopen("fractii.out","w");
int a[MAX];
int main()
{
    int n, i, j;
    int y = 0;
    if(fscanf(in,"%d",&n))
    for(i=2; i <= n; i++)
    {
        a[i] += i-1;
        for(j=2*i; j<= n; j += i)
        {
            a[j] -= a[i];
        }
        y += a[i];
    }
    fprintf(out,"%d",2*y+1);
    fclose(in);
    fclose(out);
    return 0;
}