//
// Created by liasa on 23/11/2025.
//
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define v vector
#define lp(i, s, e) for (int i = s; i < e; ++i)
#define pll pair<ll, ll>
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
ll n;
ll sum1 = 0;
cin >> n;
v<ll> a(n);
ll mx = 0;
lp(i, 0, n) {
cin >> a[i];
sum1 += a[i];
mx = max(mx, a[i]);
}
mx *= n;
mx += 2;
v<ll> dp(mx);
dp[0] = 1;
const ll mod = 1e9 + 7;
for (auto it : a) {
for (ll sum = mx - 1; sum >= it; --sum) {
dp[sum] += dp[sum - it];
dp[sum] %= mod;
}
}
if (sum1 % 2 != 0 || dp[sum1 / 2] == 0) {
cout << 0 << endl;
return 0;
}
v<ll> pos(mx + 1);
v<ll> last(mx, -1);
lp(i, 0, n) {
ll it = a[i];
ll sumi = sum1 - a[i];
for (ll sum = it; sum < mx; ++sum) {
dp[sum] -= dp[sum - it];
dp[sum] = (dp[sum] + mod) % mod;
}
for (ll j = 0; j <= sumi; ++j) {
if (dp[j] > 0) {
ll sum2 = abs(sumi - 2 * j);
if (sum2 > 0 && last[sum2] != i) {
pos[sum2]++;
last[sum2] = i;
}
}
}
for (ll sum = mx - 1; sum >= it; --sum) {
dp[sum] += dp[sum - it];
dp[sum] = (dp[sum] + mod) % mod;
}
}
v<ll> answ;
for (ll k = 1; k < mx; ++k) {
if (pos[k] == n)
answ.push_back(k);
}
cout << answ.size() << endl;
for (auto it : answ)
cout << it << " ";
}
