/// -- -- ---- --- -- --
/// 19.01.2023 Thu 15:53
/// -- -- ---- --- -- --
#include <bits/stdc++.h>
using namespace std;
#define pll pair<long long, long long>
#define all(a) (a).begin(), (a).end()
#define len(a) ((int)(a).size())
#define add push_back
#define mkp make_pair
#define ll long long
#define fr first
#define sc second
const long long INF = 1000000000ll * 1000000003ll;
const long long MOD = 1000000007ll;
const int N = 5e2 + 5;
ll n, a[N];
ll cnt[N * N];
ll ans[4 * N * N];
ll sum = 0;
void solve(){
cin >> n;
for(int i = 0; i < n; i++) cin >> a[i];
cnt[0] = 1;
for(int i = 0; i < n; i++){
sum += a[i];
for(int j = 250000 - a[i]; j >= 0; j--){
cnt[j + a[i]] += cnt[j];
}
}
if(sum % 2 == 1 || !cnt[sum / 2]){
cout << "0\n";
return;
}
for(int i = 0; i < n; i++){
for(int j = 0; j <= 250000; j++){
if(cnt[j] && j * 2 >= sum - a[i]) ans[j * 2 - sum + a[i]]++;
if(j <= 250000 - a[i]) cnt[j + a[i]] -= cnt[j];
}
for(int j = 250000 - a[i]; j >= 0; j--) cnt[j + a[i]] += cnt[j];
}
ll num = 0;
for(int i = 1; i <= 500000; i++){
if(ans[i] == n) num++;
}
cout << num << "\n";
for(int i = 1; i <= 500000; i++){
if(ans[i] == n) cout << i << " ";
}
cout << "\n";
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0);
int _ = 1;
// cout << fixed;
// cout.precision(9);
// cin >> _ ;
while(_--) solve();
return 0;
}
/// ---- - -------- ------ -------- -- - - -
/// just a reminder. ubuntu password is i o i
/// ---- - -------- ------ -------- -- - - -
