#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))
#define FOR(i, f, t)        for(int(i)=(f);(i)<(t);(++i))

int n[10010];

int main(){
    int N;
    cin >> N; N++;
    REP(i,N) cin >> n[N-i-1];

    REP(i,N-3){
        n[i+2] += n[i]; n[i] = 0;
    }
    //REP(i,N) cerr << n[i] << " "; cerr << endl;

    FOR(i,N-3,N){
        if(n[i] || i == N-1){
            cout << N-i-1 << endl << n[i];
            FOR(j,i+1,N) cout << " " << n[j];
            cout << endl;
            break;
        }
    }
    return 0;
}