#include "bits/stdc++.h"
using namespace std;
const int mod = 998244353, mod2 = (int) 1e9 + 7;
const int N = 500 * 500 + 22;
int dp[N], dp2[N];
void solve() {
int n;
cin >> n;
vector<int> a(n);
for (int i = 0; i < n; i++) {
cin >> a[i];
}
int S = std::accumulate(a.begin(), a.end(), 0);
dp[0] = dp2[0] = 1;
for (auto& x : a) {
for (int j = N - 1; j >= x; j--) {
dp[j] += dp[j - x];
if (dp[j] >= mod) {
dp[j] -= mod;
}
dp2[j] += dp2[j - x];
if (dp2[j] >= mod2) {
dp2[j] -= mod2;
}
}
}
vector<int> good(S, 0);
if (S % 2 != 0 || (dp[S / 2] == 0 && dp2[S / 2] == 0)) {
cout << 0 << '\n';
return;
}
for (int i = 0; i < n; i++) {
int x = a[i];
for (int j = x; j < N; j++) {
dp[j] -= dp[j - x];
if (dp[j] < 0) {
dp[j] += mod;
}
dp2[j] -= dp2[j - x];
if (dp2[j] < 0) {
dp2[j] += mod2;
}
}
for (int val = 1; val < S; val++) {
int Sval = S + val - x;
if (Sval % 2 != 0 || (dp[Sval / 2] == 0 && dp2[Sval / 2] == 0)) {
continue;
}
good[val]++;
}
for (int j = N - 1; j >= x; j--) {
dp[j] += dp[j - x];
if (dp[j] >= mod) {
dp[j] -= mod;
}
dp2[j] += dp2[j - x];
if (dp2[j] >= mod2) {
dp2[j] -= mod2;
}
}
}
vector<int> ans;
for (int i = 0; i < S; i++) {
if (good[i] == n) {
ans.push_back(i);
}
}
cout << ans.size() << '\n';
for (auto& i : ans) {
cout << i << " ";
}
cout << '\n';
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
// cin >> t;
while (t--) {
solve();
}
}
