#include <bits/stdc++.h>
using namespace std;
#define int ll
#define FOR(i,s,e) for(ll i = s; i <= (ll)e; ++i)
#define DEC(i,s,e) for(ll i = s; i >= (ll)e; --i)
#define IAMSPEED ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
#define db(x) cerr << #x << "=" << x << "\n"
#define db2(x, y) cerr << #x << "=" << x << " , " << #y << "=" << y << "\n"
#define db3(a,b,c) cerr<<#a<<"="<<a<<","<<#b<<"="<<b<<","<<#c<<"="<<c<<"\n"
#define dbv(v) cerr << #v << ":"; for (auto ite : v) cerr << ite << ' '; cerr <<"\n"
#define dbvp(v) cerr << #v << ":"; for (auto ite : v) cerr << "{" << ite.f << ',' << ite.s << "} "; cerr << "\n"
#define dba(a,ss,ee) cerr << #a << ":"; FOR(ite,ss,ee) cerr << a[ite] << ' '; cerr << "\n"
#define reach cerr << "LINE: " << __LINE__ << "\n";
#else
#define db(x)
#define db2(x,y)
#define db3(a,b,c)
#define dbv(v)
#define dbvp(v)
#define dba(a,ss,ee)
#define reach
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define ll long long
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define f first
#define s second
#define g0(x) get<0>(x)
#define g1(x) get<1>(x)
#define g2(x) get<2>(x)
#define g3(x) get<3>(x)
typedef pair <ll, ll> pi;
typedef tuple<ll,ll,ll> ti3;
typedef tuple<ll,ll,ll,ll> ti4;
ll rand(ll a, ll b) { return a + rng() % (b-a+1); }
const int MOD = 1e9 + 7;
const int inf = (int)1e9 + 500;
const long long oo = (ll)1e18 + 500;
template <typename T> void chmax(T& a, const T b) { a=max(a,b); }
template <typename T> void chmin(T& a, const T b) { a=min(a,b); }
const int MAXN = -1;
bitset<500005> D1[505];
bitset<500005> D2[505];
const int BUFFER=250001;
int n;
int A[505];
bitset<500005> res;
int32_t main()
{
IAMSPEED
cin >> n;
FOR(i,1,n) cin >> A[i];
res.reset();
res.flip();
FOR(i,1,n+1) {
bitset<500005> bs;
bs[BUFFER]=1;
FOR(j,1,n) {
if(i==j)continue;
bs=(bs>>A[j]) | (bs<<A[j]);
}
if(i==n+1) {
if(bs[BUFFER]==0){
return cout << 0, 0;
} else {
break;
}
}
res &= bs;
}
int cnt = 0;
FOR(i,BUFFER+1,500004)if(res[i]){
++cnt;
//cout<<i-BUFFER<<' ';
}
cout << cnt << '\n';
FOR(i,BUFFER+1,500004)if(res[i]){
cout<<i-BUFFER<<' ';
}
}
