# Given a array of numbers representing the stock prices of a company
# in chronological order, write a function that calculates the maximum
# profit you could have made from buying and selling that stock once. 
# You must buy before you can sell it.

# For example, given [9, 11, 8, 5, 7, 10], you should return 5, since
# you could buy the stock at 5 dollars and sell it at 10 dollars.







def stock_profit(lst):
	profit = []
	for x in range(len(lst)):
		for sell in lst[x+1:]:
			if sell>lst[x]:				
				profit.append(sell-lst[x])
	return max(profit)




print(stock_profit([9, 11, 8, 5, 7, 10]))