#include <iostream.h>
#include<fstream.h>
ifstream f("fractii.in");
ofstream g("fractii.out");
unsigned long t,nr,a[1000000],i,j,n;
long double b[1000000];



void divizorip(int n)
			{t=1;int i,aux=n;
			for(i=2;i<=n/2;i++)
							if(aux%i==0)
											{b[t]=i;t++;
											while(aux%i==0)aux/=i;
											}
			if(t==1)b[t]=n;
			}




int phi(long n)
		{int x=n,i;
		divizorip(n);i=1;
		while(i<=t)
				{x=x*(b[i]-1)/b[i];
						i++;
						}
			for(i=1;i<=t;i++)b[i]=0;
		return x;

		}




int main()
{
	 f>> n;
for(j=2;j<=n;j++)
		a[j]=phi(j);
for(i=1;i<=n;i++)
		nr+=a[i];
g<<2*nr+1;
	 return 0;
	 }