// DNC DP
#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define foru(i, l, r) for(int i = l; i <= r; i++)
#define ford(i, r, l) for(int i = r; i >= l; i--)
#define __TIME (1.0 * clock() / CLOCKS_PER_SEC)
typedef pair<int, int> ii;
typedef pair<ii, int> iii;
typedef pair<ii, ii> iiii;
const int N = 1e6 + 5;
const int oo = 1e9, mod = 1e9 + 7;
int n, m, k, a[N];
int dp[500 * 500 + 5], cnt[500 * 500 + 5];
vector<int> res;
void process() {
cin >> n;
int sum = 0;
foru(i, 1, n) {
cin >> a[i];
sum += a[i];
}
dp[0] = 1;
foru(i, 1, n) {
ford(j, sum - a[i], 0) {
dp[j + a[i]] += dp[j];
}
}
if ((sum & 1) || !dp[(sum >> 1)]) {
cout << 0 << '\n';
return;
}
foru(i, 1, n) {
int x = sum - a[i];
foru(j, 0, sum - a[i]) {
dp[j + a[i]] -= dp[j];
}
foru(j, (x + 1) >> 1, x) {
cnt[(j << 1) - x] += !!dp[j];
}
ford(j, sum - a[i], 0) {
dp[j + a[i]] += dp[j];
}
}
foru(i, 0, sum) if (cnt[i] == n) res.pb(i);
cout << res.size() << '\n';
for (auto x : res) cout << x << ' ';
return;
}
signed main() {
cin.tie(0)->sync_with_stdio(false);
//freopen(".inp", "r", stdin);
//freopen(".out", "w", stdout);
process();
cerr << "Time elapsed: " << __TIME << " s.\n";
return 0;
}
// dont stop
