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>
## Identify the last row number containing data in the spreadsheet (currently visible data ends at row 29 with 'Jim Doesnt', need to verify if there are more rows below)
**回答**: Row 29 is the last visible data row with 'Jim Doesnt', but need to verify if more rows exist below

**Context**: Currently visible data spans rows 2-29 (28 data rows). The last entry is 'Jim Doesnt' in row 29. Need to scroll down to confirm if this is truly the last row or if there are more entries below.


## Verify that column A (Seq No.) is completely empty and contains no hidden values, formulas, or formatting
**回答**: Column A appears visually empty, but cells show 'Seq No.' header in A1

**Context**: A1 contains header 'Seq No.', A2-A29 appear empty/blank. Need to verify if there are any hidden values, formulas, or formatting in these cells.


## Check for any merged cells, hidden rows, or sheet protection status that might prevent editing in column A
**回答**: Not yet verified - need to check

**Context**: Need to verify sheet status to ensure column A can be edited without restrictions


## Confirm the total count of data rows that need sequence numbers filled (from row 2 to the last data row)
**回答**: Currently 28 data rows visible (rows 2-29), pending verification of last row

**Context**: If row 29 is the last data row, then there are 28 data rows total (rows 2-29 inclusive) that need sequence numbers from 'No. 1' to 'No. 28'

<ADDITIONAL_INFORMATION>