#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define gcd __gcd
#define sz(v) (int) v.size()
#define pb push_back
#define pi pair<int,int>
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define ROF(i, a, b) for(int i = (a); i >= (b); i--)
#define dbg(x) "[" #x " = " << (x) << "]"
///#define int long long
using ll = long long;
using ld = long double;
using ull = unsigned long long;
template<typename T> bool ckmx(T& a, const T& b){if(a < b) return a = b, true; return false;}
template<typename T> bool ckmn(T& a, const T& b){if(a > b) return a = b, true; return false;}
const int N = 2e5+5;
const ll MOD = 1e9+7;
const ll INF = 1e18;
void solve()
{
int n; cin >> n;
vector<int> a(n + 1);
FOR(i, 1, n) cin >> a[i];
int sum = accumulate(1 + all(a), 0);
if(sum & 1) return cout << "0\n", void();
vector<ll> dp((sum / 2) + 1, 0);
dp[0] = 1;
FOR(i, 1, n){
ROF(j, sum / 2, a[i]){
dp[j] += dp[j - a[i]];
}
}
if(!dp[sum / 2]) return cout << "0\n", void();
vector<int> cnt(sum + 1, 0);
FOR(i, 1, n){
FOR(j, a[i], sum / 2){
dp[j] -= dp[j - a[i]];
}
FOR(j, 0, sum - a[i]){
if(sum - a[i] - (2 * j) <= 0) break;
if(dp[j]){
cnt[sum - a[i] - (2 * j)]++;
}
}
ROF(j, sum / 2, a[i]){
dp[j] += dp[j - a[i]];
}
}
vector<int> ans;
FOR(i, 1, sum) if(cnt[i] == n) ans.pb(i);
cout << sz(ans) << "\n"; for(int v : ans) cout << v <<" "; cout << "\n";
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#define name "InvMOD"
if(fopen(name".INP", "r")){
freopen(name".INP","r",stdin);
freopen(name".OUT","w",stdout);
}
int t = 1; //cin >> t;
while(t--) solve();
return 0;
}
