
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
In the diagram, a grid is composed of squares forming an area 15 units wide and 5 units tall. Calculate the area of the shaded region in the following grid structure:
- The grid is divided into:
  - A rectangle of 3x5 units from the left,
  - Followed by a rectangle of 4x5 units,
  - Followed by a rectangle of 8x5 units.
- A right-angled triangle unshaded with a base along the entire grid width of 15 units and a height of 5 units is located on the right end.

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