Question: PDAs with two stacks are strictly more powerful than PDAs with one stack. Prove that 2-stack PDAs are not a valid model for CFLs by

PDAs with two stacks are strictly more powerful than PDAs with one stack. Prove that 2-stack PDAs are not a valid model for CFLs by giving an example of a language that is not context-free and yet accepted by a 2-stack PDA. Describe (no math necessary) how a 2-stack PDA would accept that language.

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