Seem's like there are not just '.' and '#' in the input matrix. I've
got TL on the folowing code:

  read(n);
  for i:=1 to n do
    for j:=1 to n do begin
      if seekeof then;
      read(m[i, j]);
      if (m[i, j] <> '.') and (m[i, j] <> '#') then
        while true do;
    end;

Then I've changed it on the folowing:

  read(n);
  for i:=1 to n do
    for j:=1 to n do begin
      if seekeof then;
      read(m[i, j]);
      while (m[i, j] <> '.') and (m[i, j] <> '#') do
        read(m[i, j]);
    end;

... and got AC.

Jury, clean your tests plz - time and attempts are wasted...