#include <stdio.h>
using namespace std;
int n , v[1000001],i,j;
long long ct = 0;
int main()
{
    FILE*fin=fopen("fractii.in","r");
    FILE*fout=fopen("fractii.out","w");
    fscanf(fin,"%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];
    for(i=1;i<=n;i++)
        ct+=v[i];
    fprintf(fout,"%w",2*ct+1);

return 0;}