o62_may11_insert

#include <bits/stdc++.h>

using namespace std;
const int INF = 2e9;
const int N = 2e5 + 10;
vector <int> val;
stack <int> st;

int main(){

    int n;
    scanf("%d", &n);

    int num;
    scanf("%d", &num);

    st.push(num);
    for(int i=2;i<=n;i++){
        char opr; scanf(" %c", &opr);
        scanf("%d", &num);
        num *= (opr == '-' ? -1: 1);
        if(num < 0){
            if(!st.empty()){
                val.push_back(st.top());
                st.pop();
            }
            val.push_back(num);
        }
        else{
            int tp = 0;
            if(!st.empty()){
                tp = st.top();
                st.pop();
            }
            st.push(tp + num);
        }

    }

    if(!st.empty()){
        val.push_back(st.top());
        st.pop();
    }

    int sz = val.size();
    vector <int> qs_abs(sz + 10, 0);

    for(int i=sz-1;i>=0;i--)
        qs_abs[i] = qs_abs[i+1] + abs(val[i]);

    int sum = 0, ans = 0;
    for(int i=0;i<sz;i++){
        sum += val[i];
        ans = max(ans, sum);
        if(val[i] < 0 and i + 2 < sz)
            ans = max(ans, sum - val[i+1] + qs_abs[i+2]);
    }

    printf("%d", ans);

    return 0;
}