#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
typedef long long ll;

int main(){
  int D;
  cin >> D;
  int ans[D+1];
  FOR(i,0,D+1) cin >> ans[i];
  if(D <= 2){
    FOR(i,0,D+1) {
      printf("%d%c", ans[i], i == 2 ? '\n' : ' ');
    }
    return 0;
  }
  for (int i = D; i >= 3; i--){
    ans[i-2] += ans[i];
    ans[i] = 0;
  }
  int num = 3;
  for (int i = 2; i >= 0; i--){
    if(ans[i]==0) num--;
    else break;
  }
  cout << num << endl;
  FOR(i,0,num) {
    printf("%d%c", ans[i], i == num - 1 ? '\n' : ' ');
  }
  return 0;
}