def solve(inp):
    res = "";
    for i, c in enumerate(inp):
        res += c
        if(i == len(inp) - 1):
            break
        elif (inp[i] == ")" and inp[i + 1] == "("):
            res += "*"
        elif (inp[i] == "(" and inp[i + 1] == ")"):
            res += "1"
        elif (inp[i] == ")" and inp[i + 1] == ")"):
            res += "+1"

    return res

n = int(input())
vs = input()
print(eval(solve(vs)))