#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <unordered_set>
#include <cstdlib>
#include <cstring>
#include <string>
#include <set>
#include <map>
#include <algorithm>
#include <bitset>
#include <queue>
#include <unordered_map>
#include <fstream>
#include <random>
typedef unsigned long long ull;
typedef long long ll;
using namespace std;
const int N = 510;
const int M = 251000;
int a[N];
bitset <M> b[N];
bool ch[N][2 * M];
int main() {
int n, sm = 0;
cin >> n;
bitset <M> w;
w[0] = 1;
for (int i = 1; i <= n; i++) {
cin >> a[i];
if (a[i] % 2 != a[1] % 2) {
cout << "0\n";
return 0;
}
w |= (w << a[i]);
sm += a[i];
}
if (sm % 2 == 1) {
cout << "0\n";
return 0;
}
if (!w[sm / 2]) {
cout << "0\n";
return 0;
}
for (int i = 1; i <= n; i++) {
b[i][0] = 1;
for (int j = 1; j <= n; j++) {
if (i == j) continue;
b[i] |= (b[i] << a[j]);
}
}
for (int i = 1; i <= n; i++) {
sm -= a[i];
for (int j = 0; j <= sm; j++) {
if (b[i][j]) {
if (2 * j < sm) {
ch[i][sm - 2 * j] = true;
}
else {
ch[i][2 * j - sm] = true;
}
}
}
sm += a[i];
}
vector <int> ans;
for (int j = 1; j <= 250000; j++) {
bool flag = true;
for (int i = 1; i <= n; i++) {
if (ch[i][j]) continue;
flag = false; break;
}
if (flag) ans.push_back(j);
}
cout << (int)ans.size() << "\n";
for (auto it : ans) {
cout << it << " ";
}
cout << "\n";
}
