#include <bits/stdc++.h>
#pragma GCC optimize("O3","unroll-loops")
#pragma GCC target("avx2","popcnt")
using namespace std;
#ifdef MIKU
string dbmc = "\033[1;38;2;57;197;187m", dbrs = "\033[0m";
#define debug(x...) cout << dbmc << "[" << #x << "]: ", dout(x)
void dout() { cout << dbrs << endl; }
template <typename T, typename ...U>
void dout(T t, U ...u) { cout << t << (sizeof...(u) ? ", " : ""); dout(u...); }
#else
#define debug(...) 39
#endif
#define int long long
#define fs first
#define sc second
#define mp make_pair
#define FOR(i, j, k) for (int i = j, Z = k; i < Z; i++)
typedef pair<int, int> pii;
const int MXN = 250005;
int n, a[MXN];
int sum;
bitset<MXN> ans, b, c;
bitset<MXN> p[505];
bool check() {
if (sum & 1) return false;
ans.reset();
ans[0] = true;
FOR(i, 0, n) ans |= (ans << a[i]);
return ans[sum / 2];
}
void miku() {
cin >> n;
FOR(i, 0, n) cin >> a[i];
FOR(i, 0, n) sum += a[i];
if (!check()) {
cout << 0 << '\n' << '\n';
return;
}
ans.set();
p[0][0] = 1;
FOR(i, 0, n) p[i + 1] = p[i] | (p[i] << a[i]);
FOR(i, 0, n) {
c.reset();
b = p[i];
FOR(j, i + 1, n) b |= (b << a[j]);
FOR(j, 0, sum - a[i] + 1) if (b[j]) c[abs(sum - a[i] - 2 * j)] = true;
ans &= c;
}
cout << ans.count() << '\n';
FOR(i, 0, MXN) if (ans[i]) cout << i << ' ';
cout << '\n';
}
int32_t main() {
cin.tie(0) -> sync_with_stdio(false);
cin.exceptions(cin.failbit);
miku();
return 0;
}
