n = int(input())
mas = list(input()[:])
i = 1
while i < n:
    # print(mas[i-1], mas[i])
    if mas[i] == mas[i-1] == ")":
        mas.insert(i, "+1")
        i += 1
        n += 1
    elif mas[i] == "(" and mas[i-1] == ")":
        mas.insert(i, "*")
        i += 1
        n += 1
    elif mas[i] == ")" and mas[i-1] == "(":
        mas.insert(i, "1")
        i += 1
        n += 1

    i += 1

s = ""
for i in range(len(mas)):
    s += mas[i]
# print(s)
print(eval(s))