Examine the following code snippet for the peak-valley approach. Which line causes incorrect profit calculation?

Examine the following code snippet for the peak-valley approach. Which line causes incorrect profit calculation?

def maxProfit(prices):
    i = 0
    profit = 0
    while i < len(prices) - 1:
        while i < len(prices) - 1 and prices[i] >= prices[i+1]:
            i += 1
        valley = prices[i]
        while i < len(prices) - 1 and prices[i] <= prices[i+1]:
            i += 1
        peak = prices[i]
        profit += peak - valley
    return profit