Here is my programme: ( When submit, I read standard input }
const     max = 11;

          dx  :array[1..4] of integer = (1,0,-1,0);
          dy  :array[1..4] of integer = (0,-1,0,1);

          huong : array[1..4] of char
                = ( 'R', 'B', 'L', 'T' );
          vt    = 'RBLT';

          fi  = 'image.inp';

var       bang          :array[0..max,0..max] of byte;
          st            :array[1..max*max] of string[5];
          q             :array[1..max*max] of record x,y :longint end;

          n,a,b,kieu,so :longint;

          f             :text;

procedure doc_1;
var   i,x,y         :longint;
begin
  for i := 1 to n do
  begin
    readln(f, x, y);
    bang[x,y] := 1;

    if i = 1 then
    begin  a := x;
           b := y;
    end;
  end;
end;


procedure doc_2;
begin
  n := 0;
  repeat
    inc(n);
    readln(f, st[n]);
  until st[n] = '.';
end;


procedure input;
begin
  fillchar(bang, sizeof(bang), 0);

  assign(f, fi); reset(f);
  read(f, a);
  if eoln(f) then
  begin  n := a;
         kieu := 1;
         doc_1;
  end else
  begin  readln(f, b);
         kieu := 2;
         doc_2;
  end;
  close(f);
end;


procedure add(x,y,t :longint);
begin
  inc(so);
  q[so].x := x;
  q[so].y := y;
  bang[x,y] := t;
end;


procedure ghi(i :longint);
var    j        :byte;
       x,y      :longint;
begin
  if i = n then
  begin  writeln('.');
         exit;
  end;

  for j := 1 to 4 do
  begin
    x := q[i].x + dx[j];
    y := q[i].y + dy[j];

    if bang[x,y] = 1 then
    begin   write( huong[j] );
            add( x, y, 0);
    end;
  end;
  writeln(',');

  ghi(i+1);
end;


procedure ma1;
begin
  so := 0;
  add( a, b, 0);

  writeln(a,' ',b);
  ghi(1);
end;



procedure duyet(i :longint);
var     j,t,x,y   :longint;
        c         :char;
begin
  for j := 1 to length( st[i] ) - 1 do
  begin
    c := st[i][j];
    t := pos(c, vt);

    x := q[i].x + dx[t];
    y := q[i].y + dy[t];
    if bang[x,y] = 0 then add( x, y, 1);
  end;

  if i < n then duyet(i+1);
end;


procedure ma2;
var    i,j    :longint;
begin
  so := 0;
  add(a,b,1);
  duyet(1);

  writeln(n);
  for i := 1 to max do
    for j := 1 to max do
      if bang[i,j] = 1 then
        writeln(i,' ',j);
end;


begin
  input;
  case kieu of
  1 : ma1;
  2 : ma2;
  end;
end.

Well, this is really strange, and I can't tell you what's wrong about
your problem. But I can give you a test which might help you to find
out what's the problem:

14
1 1
1 2
1 3
2 2
3 2
3 3
3 4
3 5
4 2
4 4
5 2
5 3
5 4


Here's the answer of your program:
1 1
T,
RT,
R,
,
RT,
R,
T,
T,
RT,
T,
,
,
,
.

Here's the correct answer:
1 1
T,
RT,
R,
,
RT,
R,
T,
T,
RT,
T,
,
,
.

As you can see, you have one extra comma in your answer

Good luck!

your test notice that there are 14 points but it defines only 13
points. Anyway, thank you for your help. Could you please give me
another test that make my program false?

I think that the point is here:
"Neighbors are listed counter-clockwise starting with the right"
Try this one:
6
2 4
3 3
3 4
3 5
4 3
4 2
Here's the answer of your program:
2 4
R,
BT,
R,
,
B,
.
Here's the answer of mine:
2 4
R,
TB,
,
R,
B,
.

I hope this test is the one you need :)
Good luck!

My answer is the same as yours.
But i still got WA.

My answer is the same as his.
But I got Crash!!

shitty.Mishka I think your test is wrong because the input is not sorted:)