#include <bits/stdc++.h>
#define speed \
ios_base::sync_with_stdio(0); \
cin.tie(0); \
cout.tie(0);
#define precision \
cout.precision(30); \
cerr.precision(10);
#define ll long long
#define ld long double
#define pll pair<ll, ll>
#define pii pair<int, int>
#define forn(n) for (int i = 1; i <= n; i++)
#define forlr(l, r) for (int i = l; i != r; (l > r ? i-- : i++))
#define pb(x) push_back(x)
#define sz(x) (int)x.size()
#define mp(x, y) make_pair(x, y)
#define all(x) x.begin(), x.end()
#define pc(x) __builtin_popcount(x)
#define pcll(x) __builtin_popcountll(x)
#define F first
#define S second
using namespace std;
int n, s, a[505], dp[250005];
bitset<250005> w;
void add(int x) {
s += x;
for (int i = s - x; i >= 0; i--) dp[i + x] += dp[i];
}
void del(int x) {
for (int i = x; i <= s; i++) dp[i] -= dp[i - x];
s -= x;
}
int main() {
speed;
precision;
// code
cin >> n;
dp[0] = 1;
for (int i = 1; i <= n; i++) {
cin >> a[i];
add(a[i]);
}
if (s % 2 || !dp[s / 2]) {
cout << 0;
return 0;
}
for (int i = 0; i <= 250000; i++) w[i] = 1;
for (int i = 1; i <= n; i++) {
del(a[i]);
for (int j = 0; j <= 250000; j++) {
if ((s + j) % 2 || !dp[(s + j) / 2]) w[j] = 0;
}
add(a[i]);
}
cout << w.count() << "\n";
for (int i = 1; i <= 250000; i++)
if (w[i]) cout << i << " ";
// endl
#ifndef ONLINE_JUDGE
cerr << "\nTime elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
#endif
return 0;
}
