program punch;
var
  i,j,sum,n:integer;
  card:array [1..10000] of record
    a,b:longint;
  end;
begin
  assign (input,'punch.in');
  reset (input);
  readln (n);
  for i:=1 to n do readln (card[i].a,card[i].b);
  close (input);
  assign (output,'punch.out');
  rewrite (output);
  sum:=n;
  for i:=1 to n-1 do for j:=i+1 to n do if (card[j].a<=card[i].a) and (card[j].b>=card[i].b) then dec(sum);
  writeln (sum);
  close (output);
end.