import java.util.Scanner;

public class Yukicoder40 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int D = sc.nextInt() + 1;
		int[] a = new int[D];
		for (int i = 0; i < D; i++) a[D - i - 1] = sc.nextInt();

		for (int i = 0; i < D - 3; i++) {
			a[i + 2] += a[i];
			a[i] = 0;
		}

		int num = 0;
		for (int i = 0; i < D - 1; i++) if (a[i] != 0) num++;
		System.out.println(num);
		for (int i = 0; i < num + 1; i++) System.out.print(a[D - i - 1] + " ");
		System.out.println();
	}
}