from itertools import accumulate

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

plus = [0] * N
minus = [0] * N

for i in range(N):
    if S[i] == '+':
        plus[i] = 1
    elif S[i] == '-':
        minus[i] = 1

acc_plus = [0] + list(accumulate(plus))
acc_minus = [0] + list(accumulate(minus))

def sigma(acc, i, j):
    return acc[j] - acc[i]

ans = 0
for i in range(N):
    ans = max(sigma(acc_minus, 0, i) + sigma(acc_plus, i + 1, N) + 1, ans)

print(ans)