N = int(input())

brackets = input()

#counter = 0
brackets = list(brackets)
i = 0
while i + 1 < len(brackets):
    if brackets[i] == "(" and brackets[i + 1] == ")":
        brackets.insert(i+1, "1")
        i += 1

    if brackets[i] == ")" and brackets[i + 1] == ")":
        brackets.insert(i+1, "+1")
        i += 1

    if brackets[i] == ")" and brackets[i + 1] == "(":
        brackets.insert(i + 1, "*")
        i += 1

    i += 1

out = ""
for i in brackets:
    out += f"{i}"
#print()
#print(out)
print(eval(out))