#include<stdio.h>
#define MAXN 1000066
long long sol;
int n,i,j,a[MAXN];
int main(void)
{
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<=n;i++)
        a[i]=i-1;
    for(i=2;i<=n;i++)
    {
        for(j=i+i;j<=n;j+=i)
            a[j]-=a[i];
        sol+=a[i];
    }
    printf("%lld",sol*2+1);
    return 0;
}