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