Let S = $40, r = 8% (continuously compounded), d = 1%, s = 25%, T = 2. In this situation, the appropriate values of u and d are 1.37713 and 0.83527, respectively. Using a 2-step binomial tree, calculate the value of a $45-strike American put option.

the answer is $6.014 but i need help to solve it step by step