#include <iostream>
#include <map>
#include <vector>

using namespace std;


int main() {
    int n;
    cin >> n;

    int sum = 0;
    int maks_duzina = 0;
    map<int, int> zbirovi;
    zbirovi[0] = -1;

    int x;
    for(int i = 0; i < n; i++) {
        cin >> x;
        sum += x;

        auto it = zbirovi.find(sum);
        if(it != zbirovi.end()) {
            int duzina = i - (it->second);
            if(maks_duzina < duzina) maks_duzina = duzina;
        }
        else {
            mapa[sum] = i;
        }
    }
    return 0;
}

int main_kvadratna_slozenost() {
    int n;
    cin >> n;
    vector<int> pref(n+1);
    pref[0] = 0;

    int x;
    for(int i = 0; i < n; i++) {
        cin >> x;
        pref[i+1] = pref[i] + x;
    }

    int najduzi_segment = 0;
    for(int i = 0; i < n; i++) {
        for(int j = i+1; j <= n; j++) {
            if(pref[j] - pref[i] == 0) {
                int segm = j - i;
                if(segm > najduzi_segment) najduzi_segment = segm;
            }
        }
    }

    cout << najduzi_segment << endl;
    return 0;
}