function SizeOfMatrix(MyFile: TextFile) : integer;
var
   numb, n, numbEx: integer;
   isCorrect, firstIt: boolean;
begin
   n := 0;
   numb := 0;
   firstIt := true;
   isCorrect := true;
   while (not eof(MyFile)) and isCorrect do
   begin
      numbEx := numb;
      while not eoln(MyFile) do
      begin
         inc(numb);
         read (MyFile, numb);
      end;
      if numbEx <> numb then
         isCorrect := false;
      if firstIt then
      begin
         isCorrect := true;
         firstIt := false;
      end;
      inc(n);
      readln(MyFile);
   end;
   if isCorrect and (numb = n) then
      Result := n
   else
      Result := 0;
end;