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#include <iostream>
#define MAXN 100000
using namespace std;

int a[MAXN];
int tmp[MAXN];
int k_valid[MAXN+1];

bool is_k_valid(int n, int k) {
    for (int i=0; i < n; i++)
        tmp[i] = a[i];

    for (int i=0; i < n; i++) {
        if (tmp[i] > 0) {
            int w = tmp[i];
            if (i + k - 1 >= n)
                return false;
            for (int j=i; j < i+k; j++)
                tmp[j] -= w;
        }
        else if (tmp[i] < 0)
            return false;
    }
    return true;
}

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

    int res = 1;
    for (int i=2; i <= n; i++)
        k_valid[i] = 1;

    for (int k=2; k <= n; k++)
        if (k_valid[k]) {
            if (is_k_valid(n, k))
                res = k;
            else
                for (int i=2*k; i <= n; i += k)
                    k_valid[i] = 0;
        }

    cout << res << '\n';

    return 0;
}