
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
A and B are playing a game on a $20 \times 15$ chessboard. At the beginning, a queen is placed on the board in any square except the top right corner. Starting with A, the two players take turns moving the queen. Each move can be along a straight line or diagonal, but the queen can only move to the right, up, or right-up. The player who moves the queen to the top right corner wins. How many starting squares on this chessboard guarantee a winning strategy for A?

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