#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main() {
	int N;
	cin >> N;
	vector<int> A(N + 1);
	for (int i = 1; i <= N; ++i) {
		cin >> A[i];
		A[i] += A[i - 1];
	}
	int ans = -1;
	for (int i = 1; i <= A[N]; ++i) {
		if (A[N] % i == 0) {
			bool ok = true;
			for (int j = i; j < A[N]; j += i) {
				if (!binary_search(A.begin(), A.end(), j)) {
					ok = false;
					break;
				}
			}
			if (ok) {
				ans = A[N] / i;
				break;
			}
		}
	}
	cout << ans << endl;
	return 0;
}