program fractii;
var f,g:text; p,n,nr,i,j:integer;
begin
   assign(f,'fractii.in');reset(f);
   assign(g,'fractii.out');rewrite(g);
   readln(f,n);
   nr:=0;
   for i:=1 to n do
      begin
         for j:=1 to n do
            if i mod j<>0 then nr:=nr+1;
      end;
   nr:=nr+n-1;
   writeln(g,nr);
   close(f);close(g);
end.