#include<bits/stdc++.h>
#pragma optimize ("g",on)
#pragma GCC optimize ("inline")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize ("03")
#pragma GCC target ("sse,sse2,sse3,ssse3,sse4,popcnt,abm,avx2,mmx,fma,avx,tune=native")
#pragma comment(linker, "/stack:200000000")
//01001101 01100001 01101011 01101000 01100001 01100111 01100001 01111001
using namespace std;
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define ll long long
#define pb push_back
#define sz(a) a.size()
#define nl '\n'
#define popb pop_back()
#define ld double
#define ull unsigned long long
#define ff first
#define ss second
#define fix fixed << setprecision
#define pii pair<int, int>
#define E exit (0)
#define int long long
const int inf = 1e9, N = 25e4 + 1, mod = 998244353;
vector<pii> dir = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
int dp[N], cnt[N];
main() {
//freopen("cowrect.in", "r", stdin);
//freopen("cowrect.out", "w", stdout);
ios_base::sync_with_stdio(NULL);
cin.tie(NULL);
int n;
cin >> n;
int a[n + 1], sum = 0;
for (int i = 1; i <= n; i++) {
cin >> a[i];
sum += a[i];
}
dp[0] = 1;
for (int i = 1; i <= n; i++) {
for (int w = N - 1; w >= a[i]; w--) dp[w] += dp[w - a[i]];
}
if (!dp[sum / 2] || (sum & 1)) cout << 0, E;
for (int i = 1; i <= n; i++) {
for (int w = a[i]; w < N; w++) dp[w] -= dp[w - a[i]];
sum -= a[i];
for (int val = 0; val < N; val++) {
sum += val;
if (dp[sum / 2] && !(sum & 1)) cnt[val]++;
sum -= val;
}
sum += a[i];
for (int w = N - 1; w >= a[i]; w--) dp[w] += dp[w - a[i]];
}
vector<int> ans;
for (int val = 0; val < N; val++) if (cnt[val] == n) ans.pb(val);
cout << sz(ans) << nl;
for (auto e: ans) cout << e << ' ';
}
