var f,g:text;
    n,i,j,k:longint;
    a:array[1..10000001] of longint;
begin
        assign(f,'fractii.in');
        reset(f);
        readln(f,n);
        close(f);

        for i:=1 to n do
                a[i]:=i-1;

        for i:=2 to n do begin
                j:=2*i;
                while j<=n do begin
                        a[j]:=a[j]-a[i];
                        j:=j+i;
                        end;
                end;

        for i:=2 to n do
                k:=k+a[i];

        assign(g,'fractii.out');
        rewrite(g);
        write(g,k*2+1);
        close(g);
end.