#include <bits/stdc++.h>
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("O3")
#pragma GCC target("sse4,avx2,fma,avx")
using namespace std;
#define endl "\n"
#define entire(x) (x).begin(), (x).end()
int32_t main(){
ios::sync_with_stdio(false); cin.tie(nullptr);
int n; cin >> n;
vector<int> a(n);
bitset<250001> ans; ans[0] = 1;
for (int i = 0; i < n; i++){
cin >> a[i]; ans |= ans << a[i];
}
int sum = accumulate(entire(a), 0ll);
if (sum & 1 or !ans[sum >> 1]) { cout << 0 << endl; return 0; }
bitset<250001> cur, good, done; ans.reset(); done[0] = 1;
for (int i = 1; i <= sum; i++) ans[i] = 1;
for (int idx = 0; idx < n; idx++){
cur |= done;
for (int i = idx + 1; i < n; i++) cur |= cur << a[i];
for (int i = a[idx] & 1; i <= sum - a[idx]; i += 2) if (ans[i]) {
int target = (sum - a[idx] + i);
if (target & 1) continue; target >>= 1;
good[i] = cur[target] | cur[target - i];
} ans &= good; done |= done << a[idx];
if (idx != n-1) cur.reset(), good.reset();
}
cout << ans.count() << endl;
for (int i = 1; i <= sum; i++) if (ans[i]) cout << i << " ";
return 0;
}
