program fractii;
var S,n,i,j : longint;
    f : text;
begin
     assign(f,'fractii.in'); reset(f);
     readln(f,n);
     close(f);
     S:=n;
     i:=2;
     while i<=n do
           begin
                j:=i+1;
                while j<=n do
                      begin
                           if j mod i=1 then S:=S+1;
                           j:=j+1;
                      end;
                i:=i+1;
           end;
     assign(f,'fractii.out'); rewrite(f);
     write(f,S); reset(f);
     close(f);
end.