program Zadacha;

{$APPTYPE CONSOLE}

uses
  SysUtils;
 var i,n,j,k,m:integer;
 X,Y:array[1..200000] of integer;
 f1,f2:text;
begin
  { TODO -oUser -cConsole Main : Insert code here }
 assign(f1,'task.in');
 assign(f2,'task.out');
 reset(f1);
 rewrite(f2);
 readln(f1,n);
 for i:=1 to n do
 begin
  readln(f1,X[i],Y[i]);
 end;
 for i:=1 to n do
 begin
  m:=0;
  for j:=1 to n do
  begin
   if (i<>j) and (((X[i]<=X[j]) and (Y[i]<=Y[j])) or ((X[i]<=Y[j]) and (Y[i]<=X[j]))) then
   inc(m);
  end;
  if m<>0 then inc(k);
 end;
 writeln(f2,k);
 close(f1);
 close(f2);
end.