import java.util.Scanner;

    public class Main{

        public static void main(String[] args) {
            Scanner in = new Scanner(System.in);
            int N = in.nextInt();
            int[] a = new int[N];
            int k1 = 0;
            int k2 = 0;
            for (int i = 0 ; i < N ; i ++) {
                a[i] = in.nextInt();
            }
            for (int i = 0; i < N; i++) {
                if (a[i] % a[0] == 0) {
                    k1 = k1 + 1;
                }
                if (a[i] % a[N - 1] == 0) {
                    k2 = k2 + 1;
                }

            }
            if (k1 > k2) {
                System.out.println(1);
            }
            if (k1 < k2) {
                System.out.println(0);
            }
            if (k1 == k2) {
                System.out.println(-1);
            }
        }
    }