def chiefHopper(arr:list)->int:
    """
    LOGIC:
    We iterate the array from the end.
    If we check the formula, we got
    
    if bot energy is less than height
    newEnergy = botEnergy - (height - botEnergy) 
    and
    newEnergy = botEnergy +(botEnergy-height) if not.
    
    This two operations, when reduced get:
    newEnergy = 2*botEnergy - height
    So this is the operation we will perform from the back,
    keeping track of the result of each one to be used again
    in the inmediate before index.
		For the initial value, we need to remember that, at the end, energy needs to be more than zero.
		
		
    """
    
    minimum = 0
    for height in reversed(arr):
        minimum = ceil((height+minimum)/2)
    return minimum