#include <bits/stdc++.h>
using namespace std;
const int N = 5e2 + 5;
const int S = N * N;
bitset<S> ans;
int main () {
ios::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
vector<int> a (n + 1);
for (int i = 0; i < n; i++) cin >> a[i];
ans.set();
int whole_sum = accumulate (a.begin(), a.end(), 0);
for (int i = 0; i <= n; i++) {
// i = n;
int was = a[i];
a[i] = 0;
whole_sum -= was;
bitset<S> is_possible;
is_possible[0] = 1;
for (int j = 0; j < n; j++) {
is_possible |= (is_possible << a[j]);
}
bitset<S> Get;
bool is_there_valid = false;
for (int j = 0; j <= whole_sum; j++) {
if (is_possible[j]) {
int left = j;
int right = whole_sum - j;
// cout << left << ' ' << right << '\n';
if (i == n && left == right) is_there_valid = true;
Get[abs(left - right)] = 1;
}
}
if (i == n) {
if (!is_there_valid) {
cout << 0 << '\n';
return 0;
} else break;
}
ans &= Get;
whole_sum += was;
a[i] = was;
}
cout << ans.count() << '\n';
for (int i = 0; i < S; i++) if (ans[i]) cout << i << ' ';
return 0;
}
