#include    <stdio.h>
#define MAX 1000002
FILE * in = fopen("fractii.in","r");
FILE * out = fopen("fractii.out","w");
int main()
{
    int n, i, j, y;
    int a[MAX];
    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);
    return 0;
}