def calPoints(operations):
    score = []
    for i in range(len(operations)):
        print(score)
        if operations[i].startswith("-"):
            score.append(int(operations[i]))
        if operations[i].isdigit():
            score.append(int(operations[i]))
        if operations[i] == "+":
                score.append(score[-1] + score[-2])
        if operations[i] == "D":
            score.append(score[-1] * 2)
        if operations[i] == "C":
            score.pop()
    return sum(score)
    
# print(calPoints(["5","2","C","D","+"]))
print(calPoints(["5","-2","4","C","D","9","+","+"]))