import sys
import math
from collections import Counter
import bisect

input = sys.stdin.readline

# author: nemesis-lance

# Started solving: 2025-07-25 19:31:38
# ------------------------------------
# </> META COGNITION >/<

n = int(input())
s = input().strip()
count_p = s.count('+')
count_n = s.count('-')
p1 = n+1
p0 = n+1
p_b = 0
for i in range(n):
    if p1 != n+1 or p0 != n+1:
        break
    elif s[i] == '0':
        p0 = i
    elif s[i] != '0' and s[i] != '-':
        p1 = i
        p_b += 1

c1 = 0
if p1 > p0:
    c1 = count_p
else:
    c1 = count_p - p_b + 1
# print(c1)
n1 = -1
n0 = -1
n_b = 0
for i in range(n-1,-1,-1):
    if n1 != -1 or n0 != -1:
        break
    elif s[i] == '0':
        n0 = i
    elif s[i] != '0' and s[i] != '+':
        n1 = i
        n_b += 1
c2 = 0
# print(n1,n0)
if n1 > n0:
    c2 = count_n
else:
    c2 = count_n - n_b + 1


    
print(max(c1,c2))