#include "bits/stdc++.h"
using namespace std;
#ifdef duc_debug
#include "bits/debug.h"
#else
#define debug(...)
#endif
const int maxn = 505;
const int N = 500 * 500 + 5;
int n, a[maxn];
bitset<N> bs;
int cnt[N];
void solve() {
cin >> n;
bs[0] = 1;
int sum = 0;
for (int i = 1; i <= n; ++i) {
cin >> a[i];
bs |= (bs << a[i]);
sum += a[i];
}
if (sum & 1 || !bs[sum / 2]) {
cout << 0;
return;
}
for (int i = 1; i <= n; ++i) {
bs = 0;
bs[0] = 1;
for (int j = 1; j <= n; ++j) {
if (i == j) continue;
bs |= (bs << a[j]);
}
for (int j = (sum - a[i]) / 2; j >= 0; --j) {
if (bs[j]) {
++cnt[(sum - a[i]) - j * 2];
}
}
}
vector<int> res;
for (int i = 1; i < N; ++i) {
if (cnt[i] == n) res.push_back(i);
}
cout << (int)res.size() << '\n';
for (auto i : res) cout << i << " ";
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
