#include<iostream>
#include<vector>
using namespace std;

int main(){
    int N;
    string S;
    cin >> N >> S;

    vector<int> minus(N+2,0),plus(N+2,0);//Sの0~i文字目までに何個'-'があるか/Sのi~N-1文字目までに何個'+'があるか

    for(int j = 0; j < N; j++){
        minus[j+1] = minus[j];
        if(S[j] == '-')minus[j+1]++;
    }
    for(int j = N-1; j >= 0; j--){
        plus[j+1] = plus[j+2];
        if(S[j] == '+')plus[j+1]++;
    }

    int ans = 0;
    for(int j = 0; j < N; j++){
        ans = max(ans,minus[j-1] + 1 + plus[j+1]);
    }
    cout << ans << endl;
    return 0;
}