program Project2;
var
t : array [1..200000, 1..2] of integer;
i, j, n, k, zam : integer;
f, g : text;
procedure zamina();
var
u, m : integer;
 begin
 u := t[1, 1];
 m := t[1, 2];
 t[1, 1] :=t[zam, 1];
 t[1, 2] := t[zam, 2];
 t[zam, 1] := u;
 t[zam, 2] := m;
 end;

function perev():boolean;
var
ii, jj : integer;
bool : boolean;
begin
bool := false;
ii := 1;
  for jj := 2 to n do
  begin
   if ((t[ii, 1] < t[jj, 1]) and (t[ii, 2] <= t[jj, 2])) then
     bool := true;
   if ((t[ii, 2] < t[jj, 2]) and (t[ii, 1] <= t[jj, 1])) then
     bool := true;
   if ((t[ii, 2] < t[jj, 1]) and (t[ii, 1] <= t[jj, 2])) then
     bool := true;
   if ((t[ii, 1] < t[jj, 2]) and (t[ii, 2] <= t[jj, 1])) then
     bool := true;
  end;
perev := bool;
end;

begin
assign(f, 'task.in');
reset(f);
read(f, n);
i := 1;
while i < n +1 do
begin
 read (f, t[i, 1], t[i, 2]);
 inc(i);
end;
i := 2;
zam := 2;
k := 0;
if perev = true then
inc(k);
while i <= n do
begin
 zamina();
 if perev = true then
  inc(k);
 inc(zam);
 inc(i);
end;
assign(g, 'task.out');
rewrite(g);
writeln(g, k);
close(g);
{ TODO -oUser -cConsole Main Insert code here }
end.