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

pair_sum = op_sum = cl_sum = 0
pair = op = cl = 0
for c in S:
    if c == '(':
        op += 1
    else:
        if op > 0:
            op -= 1
            pair += 1
        else:
            cl += 1
    op_sum += op
    cl_sum += cl
    pair_sum += pair

for c in S:
    if c == '(': break
    cl_sum -= 1

print(pair_sum*2 + min(op_sum, cl_sum)*2)