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#include <algorithm>
#include <iostream>
#include <fstream>
using namespace std;
ifstream in("fractii.in");
ofstream out("fractii.out");
int v[1000001];
int main ()
{
int n, i, j, S=0;
in>>n;
for (i=2; i<=n; i++)
v[i]=i-1;
for(i=1; i<=n; i++)
{
for (j=2*i; j<=n; j=j+i)
v[j]=v[j]-v[i];
}
for (i=1; i<=n; i++) S=S+v[i];
out<<S*2+1 ;
return 0;
}