Python题解 | #矩阵乘法计算量估算#

while True:
    try:
        n = int(input())
        arr = []
        for i in range(n):
            arr.append(list(map(int, input().strip().split(' '))))
        s = input()
        order = []
        res = 0
        for i in s:
            if i.isalpha():
                order.append(arr[ord(i) - 65])
            elif i == ')' and len(order) >= 2:
                a = order.pop()
                b = order.pop()
                res += b[0] * b[1] * a[1]
                order.append([b[0], a[1]])
        print(res)


    except:
        break