def solve():
    N = int(input())
    S = "*" + input() + "*"

    left_minus = [0] * (N + 2)
    for i in range(1, N + 1):
        left_minus[i] = left_minus[i - 1]
        if S[i] == "-":
            left_minus[i] += 1

    right_plus = [0] * (N + 2)
    for i in range(N, 0, -1):
        right_plus[i] = right_plus[i + 1]
        if S[i] == "+":
            right_plus[i] += 1

    return max(left_minus[i - 1] + right_plus[i + 1] + 1 for i in range(1, N + 1))

#==================================================
print(solve())