private void helper(int row, int[] board, int[] count) {

		if (row == board.length) {
			count[0] += 1;
			return;
		}

		for (int i = 0; i < board.length; i++) {

			board[row] = i;

			if (validate(row, board)) {
				helper(row + 1, board, count);
			}
		}
	}