Step 3000

<ROLE_AND_TASK>
你是一位验证规划专家。你的职责是为给定任务定义 evidence landmarks — 一组可通过屏幕截图独立确认的视觉特征，用于在任务执行后判断任务是否成功完成。

任务：操作 Ubuntu Linux，来达成目标: Fill the Sequence Numbers as "No. #" in the "Seq No." column. Finish the work and don't touch irrelevant regions, even if they are blank.

你需要根据任务要求和已知信息，输出一组 evidence landmarks。

规则：
- 每个 landmark 必须是**可在截图中直接观察到的视觉特征**，如特定单元格的值、界面元素的状态、弹窗文字等。
- landmark 之间应相互独立，各自验证任务的不同方面。
- 所有 landmark 的组合应足以高置信度地证明任务已完成。
- 数量尽量少，但覆盖任务的所有关键变更点。不要列举未变更的内容。
- 避免模糊表述（如"文件已保存"），使用具体可观测的描述（如"标题栏不含未保存标记 *"）。

示例：
任务：在 LibreOffice Calc 创建 Sheet2, 汇总 Sheet1 中每月 API 调用量数据. A 列为 Month, B 列为 Total
背景信息：
- A 列为月份列, 包含 JAN-OCT 的数据
- B-G 为不同 API 的调用量数据列
evidence landmarks：
- "新增的 Sheet2 标签页在界面底部可见"
- "Sheet2 中 A7 单元格显示为 'JUN'"
- "Sheet2 中 A12 单元格为空"
- "Sheet2 中 B4 单元格的求和公式为 '=SUM(Sheet1.B4:G4)'"

</ROLE_AND_TASK>

<OUTPUT_SCHEMA>

调用 `define_evidence_landmarks`：
```json
{
    "evidence_landmarks": [
        str  // 可通过截图独立确认的视觉特征点
    ]
}
```

</OUTPUT_SCHEMA>


<ADDITIONAL_INFORMATION>
## What is the last row number containing data in the spreadsheet (need to verify if data ends at row 29 or continues below)?
**回答**: Data is visible from row 2 to row 29. Need to scroll down to verify if there are more rows.

**Context**: The spreadsheet currently shows rows 2-29 with data. Row 1 is the header. Column A (Seq No.) is empty for all visible rows. The data includes Order ID, Date, and Sales columns.


## Are there any existing values in column A (Seq No. column) that should not be overwritten?
**回答**: No, column A appears completely empty for all visible rows (2-29).

**Context**: Column A (Seq No.) is the first column and is currently blank/empty for all visible data rows. The header 'Seq No.' is in row 1. No existing sequence numbers are present that need to be preserved.


## What is the exact range of rows that need sequence numbers filled (start row to end row)?
**回答**: Start row is row 2. End row is at least row 29, but need to verify if data continues below.

**Context**: Row 1 contains headers. Data starts at row 2. Currently visible data ends at row 29. Need to confirm if row 29 is the last row with data or if there are more rows below.

<ADDITIONAL_INFORMATION>