#pragma GCC diagnostic ignored "-Wunused-parameter"
#pragma GCC diagnostic ignored "-Wunused-variable"
#pragma GCC diagnostic ignored "-Wparentheses"
#include <bits/stdc++.h>
#define all(i) (i).begin(), (i).end()
#define random random_device rd; mt19937 rng(rd())
using namespace std;
template<typename T1, typename T2>
ostream& operator << (ostream &i, pair<T1, T2> j) {
return i << j.first << ' ' << j.second;
}
template<typename T>
ostream& operator << (ostream &i, vector<T> j) {
i << '{' << j.size() << ':';
for (T ii : j) i << ' ' << ii;
return i << '}';
}
void Debug(bool _split) {}
template<typename T1, typename ...T2>
void Debug(bool _split, T1 x, T2 ...args) {
if (_split)
cerr << ", ";
cerr << x, Debug(true, args...);
}
template<typename T>
void Debuga(T *i, int n) {
cerr << '[';
for (int j = 0; j < n; ++j) cerr << i[j] << " ]"[j == n - 1];
cerr << endl;
}
#ifdef SYL
#define debug(args...) cerr << "\u001b[35mLine(" << __LINE__ << ") -> [" << #args << "] is [", Debug(false, args), cerr << "]\u001b[0m" << endl
#define debuga(i) cerr << "\u001b[35mLine(" << __LINE__ << ") -> [" << #i << "] is ", Debuga(i, sizeof(i) / sizeof(typeid(*i).name())), cerr << "\u001b[0m"
#else
#define debug(args...) void(0)
#define debuga(i) void(0)
#endif
typedef long long ll;
typedef pair<int, int> pi;
const int inf = 0x3f3f3f3f, lg = 20;
const ll mod = 1e9 + 7, INF = 0x3f3f3f3f3f3f3f3f;
const int N = 500, C = N * (2 * N + 1), zro = N * N;
bitset<C> is[11][2];
bool ok[C];
int a[N];
void calc(int l, int r, int dep) {
is[dep + 1][0] = is[dep][0];
int nxt = 1, pre = 0;
while (l < r) {
is[dep + 1][nxt] = is[dep + 1][pre] << a[l];
is[dep + 1][nxt] |= is[dep + 1][pre] >> a[l];
swap(nxt, pre);
++l;
}
if (pre)
is[dep + 1][0] = is[dep + 1][1];
}
void dc(int l, int r, int dep) {
if (l == r - 1) {
for (int i = zro + 1; i < C; ++i)
ok[i] = ok[i] & is[dep][0].test(i);
return;
}
int m = l + r >> 1;
calc(l, m, dep);
dc(m, r, dep + 1);
calc(m, r, dep);
dc(l, m, dep + 1);
}
signed main() {
ios::sync_with_stdio(0), cin.tie(0);
int n;
cin >> n;
for (int i = 0; i < n; ++i)
cin >> a[i];
fill(ok, ok + C, true);
is[0][0].set(zro, true);
dc(0, n, 0);
calc(0, n, 0);
if (!is[1][0].test(zro))
return cout << 0, 0;
vector<int> ans;
for (int i = zro + 1; i < C; ++i)
if (ok[i])
ans.push_back(i - zro);
cout << ans.size() << '\n';
for (int i : ans)
cout << i << ' ';
}
/*
n^2C pre,suf
k * (n^2C + n/k * n/k * nC)
T(N) = 2 * (N/2 * maxN * C + T(N/2))
= 2T(N/2) + NmaxNC
n maxn c lgn
*/
