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: Given a partial calendar, please highlight all the weekends (Satureday & Sunday) by setting the cell background as red (#ff0000). 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 are the specific dates contained in column E (October 2022) that currently display as '###' due to insufficient column width?
**回答**: Column E contains September 2022 dates, not October. October 2022 is in column F. Column F shows '###' because the column is too narrow to display the dates.

**Context**: The months are arranged in columns B-F: Jun, Jul, Aug, Sep, Oct. Column F contains October 2022 dates but is currently displaying '###' symbols due to insufficient column width.


## Are there any additional date columns to the right of column E (columns F, G, etc.) that contain calendar data?
**回答**: Column F contains October 2022 dates. There appear to be no additional date columns beyond column F (columns G onwards are empty).

**Context**: The calendar spans 5 months: June through October 2022, arranged in columns B through F. Only column F to the right of column E contains calendar data.


## What are the exact row ranges for dates in each month column (specifically: rows 3-32 for Jun/Sep, rows 3-33 for Jul/Aug, and what range for Oct)?
**回答**: June (column B): rows 3-32 (30 days), July (column C): rows 3-33 (31 days), August (column D): rows 3-33 (31 days), September (column E): rows 3-32 (30 days), October (column F): appears to start at row 3, but exact end row is not visible due to '###' display.

**Context**: Row ranges vary by month length: 30-day months (Jun, Sep) occupy rows 3-32; 31-day months (Jul, Aug) occupy rows 3-33. October is a 31-day month so should occupy rows 3-33.


## Which specific dates in the calendar fall on Saturdays and Sundays, or alternatively, what day of the week does the first day of each month fall on?
**回答**: Partially visible. Need to see all October dates first. From visible data: June 1, 2022 is Wednesday; July 1, 2022 is Friday; August 1, 2022 is Monday; September 1, 2022 is Thursday; October 1, 2022 is Saturday.

**Context**: October 1, 2022 falls on Saturday (visible in row 3, column F). This means October weekends are: 1-2, 8-9, 15-16, 22-23, 29-30. Need to verify all dates are visible by widening column F.

<ADDITIONAL_INFORMATION>