program Ural1078;

var
  ok:array[1..500,1..500]of boolean;
  x,y,ans:array[1..500]of longint;
  a,b,n,max:longint;

function dfs(o,l:longint):boolean;

var
  i:longint;
  u:boolean;

begin
  u:=false;
  for i:=1 to n do
    if ok[o,i] then u:=u or dfs(i,l+1);
  if max<l then begin
    max:=l;
    u:=true;
  end;
  if u then ans[l]:=o;
  exit(u);
end;

begin
  readln(n);
  fillchar(ok,sizeof(ok),false);
  for a:=1 to n do
    readln(x[a],y[a]);
  for a:=1 to n do
    for b:=1 to n do
      if (x[a]<=x[b])and(y[b]<y[a]) then ok[a,b]:=true;
  max:=0;
  for a:=1 to n do
    if dfs(a,1) then ans[1]:=a;
  writeln(max);
  for a:=max downto 1 do
    write(ans[a],' ');
end.

What is wrong???