#include <iostream>
#include <string>
#include <algorithm>
#include <cmath>
#include <vector>
#include <array>
#include <set>
#include <iomanip>
#include <queue>
#include <deque>
/*
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native") // Enable AVX/AVX2
#pragma GCC optimize("Ofast")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("unswitch-loops")
#pragma GCC optimize("fast-math")
#pragma GCC optimize("rename-registers") // Optimization flags
*/
using namespace std;
using ll = long long;
using db = double;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
ll n; cin >> n;
ll p = 0;
vector<ll> a(2 * n + 1000, 0);
for (ll i = 1; i < n + 1; i++) {
cin >> a[i];
p += a[i];
}
vector<ll> dp(5e5, 0), ans(5e5, 0);
dp[0] = 1;
ans[0] = n + 1;
for (ll i = 1; i < n + 1; i++) {
for (ll j = p; j >= 0; j--)
dp[j + a[i]] += dp[j];
}
vector<ll> res;
for (ll i = 1; i <= n; i++) {
p -= a[i];
for (ll j = 0; j <= p; j++) {
dp[j + a[i]] -= dp[j];
ll x = max(j + j - p, 0ll);
if (dp[j] != 0)
ans[x]++;
if (ans[x] == n)
res.push_back(x);
}
for (ll j = p; j >= 0; j--)
dp[j + a[i]] += dp[j];
p += a[i];
}
if (dp[p / 2] == 0) {
cout << 0;
return 0;
}
cout << res.size() << endl;
for (ll x : res)
cout << x << " ";
return 0;
}
