#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define mp make_pair
#define eb emplace_back
#define pb push_back
#define X first
#define Y second
#define pii pair<int, int>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T i, U ...j) {
cout << i << ' ', abc(j...);
}
template <typename T> void printv(T l, T r) {
for (; l != r; ++l)
cout << *l << " \n"[l + 1 == r];
}
#define test(x...) abc("[" + string(#x) + "]", x);
const int N = 500 * 500 + 5;
bitset <N> dp;
int main () {
ios::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector <int> a(n);
int sum = 0;
dp.flip(0);
for (int i = 0; i < n; ++i) {
cin >> a[i];
sum += a[i];
dp |= dp << a[i];
}
if (sum & 1 || !dp[sum >> 1]) {
cout << 0 << endl << endl;
} else {
vector <int> ans(N, 0);
for (int i = 0; i < n; ++i) {
sum -= a[i];
dp.reset(), dp.flip(0);
for (int j = 0; j < n; ++j) if (i != j)
dp |= dp << a[j];
for (int j = 0; j <= sum / 2; ++j) if (dp[j])
ans[abs(sum - j - j)]++;
sum += a[i];
}
int cnt = 0;
for (int i : ans) if (i == n)
cnt++;
cout << cnt << endl;
for (int i = 0; i < N; ++i) if (ans[i] == n)
cout << i << ' ';
cout << endl;
}
}
