//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ordered_set tree <pair <int, int>, null_type, less <pair <int, int> >, rb_tree_tag, tree_order_statistics_node_update>
using namespace __gnu_pbds;
#define ll long long
#define db double
#define pb push_back
#define ppb pop_back
#define fi first
#define se second
#define mp make_pair
#define size(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define endl "\n"
//#define int long long
using namespace std;
void dout() {
cerr << endl;
}
template <typename Head, typename... Tail>
void dout(Head H, Tail... T) {
cerr << H << ' ';
dout(T...);
}
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef pair <int, int> pii;
const int N = 503, K = 250001;
const pii MOD = {1e9 + 7, 1e9 + 9};
int n, a[N], ans[K], res[K];
pii dp[K];
void add(pii & x, pii y) {
x.fi += y.fi;
if (x.fi >= MOD.fi) {
x.fi -= MOD.fi;
}
x.se += y.se;
if (x.se >= MOD.se) {
x.se -= MOD.se;
}
}
void sub(pii & x, pii y) {
x.fi -= y.fi;
if (x.fi < 0) {
x.fi += MOD.fi;
}
x.se -= y.se;
if (x.se < 0) {
x.se += MOD.se;
}
}
bool exist(int x) {
return dp[x].fi > 0 || dp[x].se > 0;
}
void solve(int tc) {
// check for (int i = 0; i < n; j++)
cin >> n;
dp[0] = {1, 1};
int total = 0;
for (int i = 1; i <= n; i++) {
cin >> a[i];
total += a[i];
for (int j = K - 1; j >= a[i]; j--) {
add(dp[j], dp[j - a[i]]);
}
}
if ((total & 1) || !exist(total >> 1)) {
cout << 0;
return;
}
fill(ans, ans + K, 1);
for (int i = 1; i <= n; i++) {
for (int j = a[i]; j < K; j++) {
sub(dp[j], dp[j - a[i]]);
}
total -= a[i];
memset(res, 0, sizeof(res));
for (int j = total & 1; j <= total; j += 2) {
if (exist(total + j >> 1) || exist(total - j >> 1)) {
res[j] = 1;
}
}
for (int j = 0; j < K; j++) {
ans[j] &= res[j];
}
memset(res, 0, sizeof(res));
total += a[i];
for (int j = K - 1; j >= a[i]; j--) {
add(dp[j], dp[j - a[i]]);
}
}
int cnt = 0;
for (int i = 0; i < K; i++) {
if (ans[i]) {
cnt++;
}
}
cout << cnt << endl;
for (int i = 0; i < K; i++) {
if (ans[i]) {
cout << i << " ";
}
}
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
int tc = 1;
// cin >> tc;
for (int i = 0; i < tc; i++) {
solve(i);
// cleanup();
}
}
