#include<stdio.h>
#include<math.h>
#define DIM 1000001
long long n,s,a[DIM];
int main ()
{
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    int i,j;
    scanf("%lld",&n);
    for(i=1;i<=n;++i)
        a[i]=i-1;
    for(i=2;i<=n;++i)
        for(j=2*i;j<=n;j+=i)
            a[j]-=a[i];
    for(i=1;i<=n;i++)
        s+=a[i];
    printf("%llu",2*s+1);
    return 0;
}