#include <bits/stdc++.h>
using namespace std;
using ll = long long;



void solve(){
    int N; cin >> N;
    int cnt0 = 0, cnt1 = 0;
    string S; cin >> S;
    for(auto c: S){
        if(c == '+') ++cnt1;
    }
    int ans = cnt0 + cnt1;
    for(auto c: S){
        ans = max(ans, cnt0 + cnt1);
        if(c == '-') ++cnt0;
        if(c == '+') --cnt1;
        if(c == '0') ans = max(ans, cnt1 + cnt0 + 1);
        ans = max(ans, cnt0 + cnt1);
    }
    cout << ans << "\n";
    
}


int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << setprecision(10) << fixed;


    int T;
    T = 1;
    //cin >> T;
    for(;T--;) solve();
}