var f : text;
    n, i, nr, c, x, j  : longint;
    ok : boolean;

begin
     assign(f,'fractii.in'); reset(f);
     readln(f,n);
     nr := n ;
     for i := 2 to n do begin
         c := i;
         ok := true;
         x := 1;
         j := 2;


         while ok or (j <= c) do begin
          ok := false;

          while (c mod j = 0) do begin
               c := c div j;
               ok := true;
          end;
          if ok then x := x * j;
          inc(j);
         end;


         nr := nr + n - n div x;
         inc(j);
     end;
     close(f);
     assign(f,'fractii.out'); rewrite(f);
     writeln(f,nr);
     close(F);
end.