#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP(i,n,0)
#define REP(i,s,e) for (i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)
#define INF 1e8

typedef long long ll;

int main() {
    int i, d;
    int a[10001] {};
    cin >> d;
    rep (i,d+1) cin >> a[i];
    RREP (i,d,3) a[i-2] += a[i];
    d = 0;
    rep (i,3) if (a[i] != 0) d = i;
    cout << d << endl;
    rep (i,d+1) cout << a[i] << " ";
    cout << endl;
    return 0;
}