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

int n;
vector<int> a;

bool czy_ok(int len) {
    vector<int> close(n, 0);

    int cur_min = 0;
    for(int i = 0; i < n; ++i) {
        cur_min -= close[i];

        if(a[i] < cur_min) {
            return false;
        }

        if(i + len - 1 >= n) {
            if(a[i] != cur_min) {
                return false;
            }
        }
        else {
            int roznica = a[i] - cur_min;
            cur_min += roznica;
            if(i + len < n) {
                close[i + len] += roznica;
            }
        }
    }
    return true;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    
    cin >> n;
    a.resize(n);
    for(int i = 0; i < n; ++i) {
        cin >> a[i];
    }

    ll sum = 0;
    for(int i = 0; i < n; ++i) {
        sum += a[i];
    }

    int ans = -1;
    for(ll i = n; i >= 1; --i) {
        if(sum % i == 0) {
            if(czy_ok(i) == true) {
                ans = i;
                break;
            }
        }
    }

    cout << ans << '\n';
}