I think I'd check the flop, and probably fold to a shove. We've invested 17BB's, but will end up making that 57BB's with any action just to find out whether our 2nd pair is good. If you have any notion he is a bad player though, I'd CRAI, as his AF will mean he could bet that flop with a lot of hands, and being a bad player might have called with a lot more hands that you are still ahead of. ie he shouldn't be calling a 3 bet for 20% of his stack with 66 here.

Against an aggressive SS I'd also CRAI with AK here.

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