var i, j, n:longint;
    a:array [1..1000000] of longint;
    k:qword;
    f, g:text;
begin assign(f,'fractii.in');
      assign(g,'fractii.out');
      reset(f); rewrite(g);
      readln(f, n);
      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:=1 to n do k:=k+a[i];
      writeln(g, k*2+1);
      close(f); close(g);
end.