#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, n) for (int i = a; i < (int)(n); i++)
using ll = long long;

int main()
{
    int n;
    string s;
    cin >> n >> s;
    vector<int> minus(n + 1, 0), plus(n + 1, 0);
    rep(i, 0, n)
    {
        minus[i + 1] = minus[i], plus[i + 1] = plus[i];
        if (s[i] == '-')
        {
            minus[i + 1]++;
        }
        else if (s[i] == '+')
        {
            plus[i + 1]++;
        }
    }
    int ans = 0;
    rep(i, 0, n)
    {
        if (s[i] == '0')
        {
            ans = max(ans, minus[i] + plus[n] - plus[i] + 1);
        }
        else if (s[i] == '+')
        {
            ans = max(ans, minus[i] + plus[n] - plus[i - 1]);
        }
        else
        {
            ans = max(ans, minus[i] + plus[n] - plus[i]);
        }
    }
    cout << ans << endl;
}