import java.util.Scanner;

public class Main40 {
	public static void main(String[] args) {
		Main40 p = new Main40();
	}

	public Main40() {
		Scanner sc = new Scanner(System.in);
		int d = sc.nextInt();
		int[] a = new int[d+1];
		for(int i=a.length-1;i>=0;i--){
			a[i] = sc.nextInt();
		}
		
		solve(a);
	}

	public void solve(int[] a) {
		for(int i=0;i<a.length-3;i++){
			a[i+2] += a[i];
			a[i] = 0;
		}
		
		int first = 0;
		while(first < a.length && a[first]==0){
			first++;
		}
		
		if(first == a.length){
			System.out.println("0\n0");
		}else{
			System.out.println(a.length-first-1);
			for(int i=a.length-1;first<i;i--)
				System.out.print(a[i]+" ");
			System.out.println(a[first]);
		}
	}

}