n = int(input())
s = input().strip()

x = 0
while x < len(s) and s[x] == ')':
    x += 1

L_total = 0
R_total = 0
for j in range(n):
    if s[j] == '(':
        L_total += (n - j)
    else:
        R_total += (n - j)

effective_r = max(0, R_total - x)
ans = 2 * min(L_total, effective_r)
print(ans)