
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Find the number of square units in the area of the shaded region. The region is bounded by a square and two triangles within the square. The vertices of the square are at (0,0), (40,0), (40,40), and (0,40). The vertices of the shaded region are (0,0), (10,0), (40,30), (40,40), (30,40), and (0,20).

Present the answer in LaTex format: \boxed{Your answer}
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