#include <bits/stdc++.h>
#define endl '\n'
using namespace std;
const int MAX_N = 505;
const int MAX_SUM = 500 * 500 + 5;
int a[MAX_N], dp[MAX_SUM], aux[MAX_SUM], cntOkWith[MAX_SUM];
int main() {
//ios_base::sync_with_stdio(false);
//cin.tie(nullptr);
int n;
cin >> n;
int sum = 0;
dp[0] = 1;
for(int i = 0; i < n; i++) {
cin >> a[i];
for(int j = sum; j >= 0; j--) {
dp[j + a[i]] += dp[j];
}
sum += a[i];
}
if(sum % 2 != 0 || dp[sum / 2] == 0) {
cout << 0 << endl;
return 0;
}
for(int i = 0; i < n; i++) {
for(int j = 0; j <= sum; j++) {
aux[j] = dp[j];
}
for(int j = a[i]; j <= sum; j++) {
aux[j] -= aux[j - a[i]];
}
for(int j = 1; j <= sum; j++) {
int newSum = sum - a[i] + j;
if(newSum % 2 == 0 && aux[newSum / 2] != 0) {
cntOkWith[j]++;
}
}
}
vector< int > ans;
for(int i = 1; i <= sum; i++) {
if(cntOkWith[i] == n) {
ans.push_back(i);
}
}
cout << ans.size() << endl;
for(int x : ans) {
cout << x << " ";
}
cout << endl;
return 0;
}
