#include <bits/stdc++.h>
using namespace std;
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int N;
cin >> N;
vector<int> a(N);
for (int &value : a) {
cin >> value;
}
int S = accumulate(a.begin(), a.end(), 0);
for (int i = 0; i < N; i++) {
if (a[i] % 2 != a[0] % 2 || S % 2) {
cout << "0\n";
exit(0);
}
}
vector<uint64_t> rnd(N);
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
for (int i = 0; i < N; i++) {
rnd[i] = rng();
}
vector<uint64_t> dp(S + 1);
dp[0] = 1;
for (int i = 0; i < N; i++) {
for (int j = S - a[i]; j >= 0; j--) {
dp[j + a[i]] += dp[j];
}
}
if (dp[S / 2] == 0) {
cout << "0\n";
exit(0);
}
vector<bool> good(S + 1, true);
for (int i = 0; i < N; i++) {
for (int j = 0; j + a[i] <= S; j++) {
dp[j + a[i]] -= dp[j];
}
vector<bool> new_good(S + 1);
for (int j = 0; j <= S; j++) {
if (dp[j] > 0) {
new_good[abs(2 * j - (S - a[i]))] = true;
}
}
for (int j = 0; j <= S; j++) {
good[j] = good[j] && new_good[j];
}
for (int j = S - a[i]; j >= 0; j--) {
dp[j + a[i]] += dp[j] * rnd[i];
}
}
vector<int> answer;
for (int i = 1; i <= S; i++) {
if (good[i]) {
answer.push_back(i);
}
}
int k = (int)answer.size();
cout << k << "\n";
for (int i = 0; i < k; i++) {
cout << answer[i] << " \n"[i + 1 == k];
}
}
