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

ans = 1

A = [0] # 自分より右に+が何個あるか
B = [0] # 自分より左に-が何個あるか

for i in range(1, N):
    if S[i-1] == "-":
        B.append(B[-1] + 1)
    else:
        B.append(B[-1])

for i in range(N-2, -1, -1):
    if S[i+1] == "+":
        A.append(A[-1] + 1)
    else:
        A.append(A[-1])
    
A.reverse()


for i in range(N):
    ans = max(ans, 1 + A[i] + B[i])

print(ans)
#print(A)
#print(B)