#include <vector>
#include<iostream>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <fstream>
#include <string>
#include <set>
#include <deque>
#include <queue>
#include <map>
#include <bitset>
#include <random>
#include <cassert>
#include <unordered_map>
#include <unordered_set>
#include<math.h>
using namespace std;
typedef unsigned int ui;
typedef long long             ll;
typedef unsigned long long     ull;
typedef long double            ld;
#define endl              "\n"
#define all(a)            a.begin(), a.end()
#define allr(a)           a.rbegin(), a.rend()
#define pb                push_back
#define pikachu           push_back
#define F                 first
#define S                 second
void solve() {
    ll n,sum_now=0;
    cin >> n;
    vector<ll> a(n),dp(30000,0);
    dp[0] = 1;
    for (ll i = 0; i < n; i++){
        cin >> a[i];
        for (ll j = sum_now; j >= 0; j--)
            dp[j + a[i]] += dp[j];
        sum_now += a[i];
    }
    if (sum_now&1){
        cout << 0 << endl;
        return;
    }
    if (!dp[sum_now / 2]) {
        cout << 0 << endl;
        return;
    }
    vector<bool> ban_ans(25001, false),used(501,false);
    for (ll i = 0; i < n; i++) {
        if (!used[a[i]]) {
            used[a[i]] = true;
            sum_now -= a[i];
            for (ll j = 0; j <= sum_now; j++)
                dp[j + a[i]] -= dp[j];
            for (ll j = 1; j <= 25000; j++) {
                if ((sum_now + j) & 1)
                    ban_ans[j] = true;
                if (!dp[(sum_now + j) / 2])
                    ban_ans[j] = true;
            }
            for (ll j = sum_now; j >= 0; j--)
                dp[j + a[i]] += dp[j];
            sum_now += a[i];
        }
    }
    vector <ll> ans;
    for (ll i = 1; i <= 25000; i++)
        if (!ban_ans[i]) ans.pb(i);
    cout << ans.size() << endl;
    for (ll& i : ans) {
        cout << i << ' ';
    }
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    ll t = 1;
    //cin >> t;
    //cout << fixed << setprecision(18);
    while (t--) {
        solve();
    }
}