Problem 2 a customized asian floating strike put option in

Question

Problem 2. A customized Asian floating strike Put option in a 2-period binomial tree pays out

_max(0, (S_o + S₁ + S₂) S₂)

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where Si is the stock price at the end of the i-th period. If So = 40, r = 0.045, o = 0.15, 6 = 0 and each period is 2 months long, find the no-arbitrage price of this Asian option today.