#include <bits/stdc++.h>
using namespace std;
#define int long long
int32_t main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
int n;
cin >> n;
int sm = 0;
vector<int> a(n + 1);
for (int i = 1; i <= n; i++) {
cin >> a[i];
sm += a[i];
}
vector<int> dp(sm + 1, 0); dp[0] = 1;
for (int i = 1; i <= n; i++) {
for (int j = sm - a[i]; j >= 0; j--) {
dp[j + a[i]] += dp[j];
}
}
if ((sm & 1) || !dp[(sm>>1)]) {
return cout << 0, 0;
}
vector<int> cnt(sm + 1, 0);
for (int i = 1; i <= n; i++) {
int x = sm - a[i];
for (int j = 0; j <= sm - a[i]; j++) {
dp[j + a[i]] -= dp[j];
}
for (int j = ((x + 1)>>1); j <= x; j++) {
cnt[(j<<1) - x] += !!dp[j];
}
for (int j = sm - a[i]; j >= 0; j--) {
dp[j + a[i]] += dp[j];
}
}
vector<int> v;
for (int i = 0; i <= sm; i++) {
if (cnt[i] == n) v.push_back(i);
}
cout << (int)v.size() << "\n";
for (auto i : v) {
cout << i << ' ';
}
}
