Consider a two-step binomial tree. Each step represents 6 months. The current price of a non-dividend paying stock is $80. The risk-free rate is 3% per annum (continuous compounding). The up rate is u=1.1198=1/d. Use the tree to estimate the value of a long bear spread constructed from (i) a one-year European put option with a strike price of $77; (ii) a one-year European put option with a strike price of $83; (keep four decimals)