This is my program:
var
  t,total,k:longint;
  n,s:integer;

procedure init;
begin
  read(n,s);
  total:=0;
  k:=0;
end;

procedure work;
var
  i:integer;
begin
  for i:=9 downto 0 do
    if (total+i<=s div 2)and(k<=n) then
      begin
        inc(k);
        total:=total+i;
        if (total=s div 2)and(k=n) then inc(t)
          else work;
        total:=total-i;
        dec(k);
      end;
end;

procedure print;
begin
  writeln(t*t);
end;

begin
  init;
  work;
  print;
end.

What did you mean? I cannot get it! My English is poor!