#include using namespace std; inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;} template inline string toString(T x) {ostringstream sout;sout< inline T sqr(T x) {return x*x;} typedef vector vi; typedef vector vvi; typedef vector vs; typedef pair pii; typedef long long ll; #define all(a) (a).begin(),(a).end() #define rall(a) (a).rbegin(), (a).rend() #define pb push_back #define mp make_pair #define each(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i) #define exist(s,e) ((s).find(e)!=(s).end()) #define range(i,a,b) for(int i=(a);i<(b);++i) #define rep(i,n) range(i,0,n) #define clr(a,b) memset((a), (b) ,sizeof(a)) #define dump(x) cerr << #x << " = " << (x) << endl; #define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl; const double eps = 1e-10; const double pi = acos(-1.0); const ll INF =1LL << 62; const int inf =1 << 29; int dp[1010][2]; int trace[1010][2]; int v[1010]; int main(void){ int n; cin >> n; rep(i,n) cin >> v[i]; dp[0][0]=0; rep(i,n){ dp[i+1][0]=dp[i][0],trace[i+1][0]=2*i; if(dp[i+1][0]dp[n][0]) num=1; while(cur){ if(num) ans.pb(cur); int ncur=trace[cur][num]>>1; int nnum=trace[cur][num]&1; cur=ncur,num=nnum; } sort(ans.begin(),ans.end()); cout << max(dp[n][0],dp[n][1]) << endl; rep(i,ans.size()) cout << (i?" ":"") << ans[i]; cout << endl; return 0; }