#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int N = 5e2 + 5;
const int NN = N * N;
#define pb push_back
#define sz size()
#define ff first
#define ss second
int sum, n, dp[NN], san[NN], a[N];
vector <int> jog;
int main () {
// freopen("input.txt", "r", stdin);
cin >> n;
for (int i = 1; i <= n; ++i) {
cin >> a[i];
sum += a[i];
}
dp[0] = 1;
for (int i = 1; i <= n; ++i) {
for (int j = sum - a[i]; j >= 0; j--) {
if (dp[j]) {
dp[j + a[i]] += dp[j];
}
}
}
if (sum % 2 == 1 or !dp[sum / 2]) return cout << "0", 0;
for (int i = 1; i <= n; ++i) {
for (int j = a[i]; j <= sum; ++j) {
dp[j] -= dp[j - a[i]];
}
for (int j = 0; j <= sum; ++j) {
// optimization etmeli
int x = sum - a[i] + j;
if (x % 2 == 0 and x / 2 - j >= 0 and dp[x / 2 - j]) {
san[j]++;
}
}
for (int j = sum - a[i]; j >= 0; j--) {
dp[j + a[i]] += dp[j];
}
}
for (int i = 0; i <= sum; ++i) {
if (san[i] == n) {
jog.pb (i);
}
}
cout << (int)jog.sz << endl;
for (int i : jog) {
cout << i << " ";
}
}
