import java.util.Scanner;

public class Main {

    static Scanner in = new Scanner(System.in);

    public static void main(String[] args) {
        int n = in.nextInt();
        int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = in.nextInt();
        }
        boolean f = false;
        for (int i = 0; i + 2 < n; i++) {
            if (a[i + 1] % a[i] == 0) {
                int d = a[i + 1] / a[i];
                if (a[i + 2] == a[i + 1] * d) {
                    f = true;
                    System.out.print(a[i] + " " + a[i + 1] + " " + a[i + 2] + " ");
                    i += 2;
                    while (i + 1 < n && a[i + 1] == a[i] * d) {
                        System.out.print(a[i + 1] + " ");
                        i++;
                    }
                    System.out.println();
                }
            }
        }
        if (!f) {
            System.out.println("Not found");
        }
    }
}