int Tetris::findLowestCopmpleteLine() {
  for(size_t y = Y_GLASS_SIZE; y != 0; --y) {
    bool completeLine = true;
    for(size_t x = 1; x<= X_GLASS_SIZE ; ++x) {
      if (GetChar(x, y) == kEmptySymbol) {
        completeLine = false;
        break;
      }
    }
    if (completeLine) {
      return y;
    }
  }
  return -1;
}

bool Tetris::tryRemoveCompleteLine() {
  int complete_line = findLowestCopmpleteLine()
  if (complete_line != -1) {
    for (size_t y = complete_line; y!= 1; --y) {
      for (size_t x = 1; x <= X_GLASS_SIZE; ++x) {
        upper_row_symbol = GetChar(x, y-1);;
        SetChar(x, y, upper_row_symbol);
      }
      for (size_t x = 1; x <= X_GLASS_SIZE; ++x) {
        SetChar(x, 1, kEmptySymbol);
      }
    }
    return true;
  } else {
    return false;
  }
}

int Tetris::removeCompleteLinesAndDownCells() {
  score = 0;
  while (tryRemoveCompleteLine()) ++score;
  return score;
}