In time 0, an investor takes a calendar spread by selling two-year European call option and buying three-year European call option. These two options have the same strike price of $80 and are for the same stock that pays no dividends. The two-year option sells for $5 and the three-year option sells for $7. Two years later, the stock price turns out to be $90. The risk-free rate is 2% per annum. What is the minimum of the profit from this strategy? (We assume that we sell the longer-term option in year two).