class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        total = 0
        size = len(prices)
        l = h = -1
        i = 0
        while i < size -1:
            while i < size -1 and prices[i] >= prices[i+1]:
                i += 1
            l = prices[i]
            while i < size -1 and prices[i] < prices[i+1]:
                i += 1
            h = prices[i]
            total += h-l
        return total