#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "algo/debug.h"
#endif
#define f first
#define s second
template<class T> using V = vector<T>;
using vi = V<int>;
using vb = V<bool>;
using vs = V<string>;
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define pb push_back
#define lb lower_bound
#define ub upper_bound
template<class T> int lwb(V<T>& a, const T& b) { return lb(all(a),b)-bg(a); }
template<class T> int upb(V<T>& a, const T& b) { return ub(all(a),b)-bg(a); }
int n;
const int max_n = 500;
const int max_c = 500;
const int max_bit = max_n*max_c;
bitset<max_bit+1> dp;
vi ans;
int sum, a[max_n];
void dnc(int l, int r) {
if (l == r-1) {
vi cand;
for (int i = 0; i <= max_bit; i++) if (dp.test(i)) {
if (i < sum-a[l]-i) {
cand.pb(sum-a[l]-i - i);
}
if (i > sum-a[l]-i) {
cand.pb(i - (sum-a[l]-i));
}
}
sort(all(cand));
// ps(cand);
auto ANS = ans; ans.clear();
set_intersection(all(cand), all(ANS), back_inserter(ans));
return;
}
auto DP = dp;
int m = (l+r)/2;
for (int i = m; i < r; i++) dp |= (dp << a[i]);
dnc(l, m);
dp = DP;
for (int i = l; i < m; i++) dp |= (dp << a[i]);
dnc(m, r);
}
void solve() {
cin >> n;
for (int i = 1; i <= max_bit; i++) ans.pb(i);
dp.set(0);
for (int i = 0; i < n; i++) cin >> a[i], sum += a[i];
// check that Tima may sit out
{
dp.set(0);
for (int i = 0; i < n; i++) dp |= dp << a[i];
if (sum % 2 || !dp.test(sum/2)) {
cout << 0 << '\n';
return;
}
dp.reset();
}
dp.set(0);
dnc(0, n);
cout << ans.size() << '\n';
for (int skill : ans) cout << skill << ' ';
if (ans.size()) cout << '\n';
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
solve();
return 0;
}
