N = int(input())
S = input()

R = 0  # (((
LR = []  # ))((
L = 0  # ))

ans = 0

add = 0
cntL = 0
cntR = 0
for s in S:
    if s == ")":
        if cntR:
            cntR -= 1
            add += 2
        else:
            cntL += 1
    elif s == "(":
        cntR += 1

    ans += add

    if cntL and cntR:
        LR.append((cntL, cntR))
    elif cntL:
        L += cntL
    elif cntR:
        R += cntR


LR.sort(key=lambda x: (x[0], -x[1]))
for l, r in LR:
    d = min(R, l)
    ans += 2 * d
    R -= d
    R += r
d = min(R, L)
ans += 2 * d

print(ans)