#include<stdio.h>
int ciur[1000010];
int main()
{
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    int rez,i,n,j;
    scanf("%d",&n);
    for(i=1;i<=n;i++)
        ciur[i]=i-1;
    for(i=2;i<=n;i++)
        for(j=i+i;j<=n;j+=i)
            ciur[j]-=ciur[i];
    rez=0;
    for(i=1;i<=n;i++)
        rez+=ciur[i];
    rez=rez*2;
    rez++;
    printf("%d\n",rez);
    return 0;
}