n: int = int(input())
inp: str = input()

n_left: int = 0
n_right: int = 0
acc: str = [];
for idx in range(len(inp) - 1):
    # print(inp[idx] + inp[idx + 1])
    x = inp[idx]
    y = inp[idx + 1]
    if x == '(' and y == '(':
        acc.append("((")
        n_left += 2
        continue
    elif x == '(' and y ==  ')':
        acc.append("(1)")
        continue
    elif x == ')' and y ==  ')':
        acc.append(")+1)")
        continue
    elif x == ')' and y ==  '(':
        acc.append("*")
        continue

#print(acc)
expr: str = "".join(acc)
print(eval(expr))
#sol: str = [eval(x) for x in acc]
#print(sol)