#include<cstdio>
#define NMAX 1000005
using namespace std;
int v[NMAX];
int main()
{
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    int n,i,j;
    long long k=0;
    scanf("%d",&n);
    for(i=1; i<=n; ++i)
        v[i]=i-1;
    for(i=2; i<=n; ++i)
    {
        for(j=2*i; j<=n; j+=i)
            v[j]-=v[i];
        k+=v[i];
    }
    printf("%lld",k*2+1);
}