// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T> using ordered_set = tree<T,null_type,less_equal<T>,rb_tree_tag,
tree_order_statistics_node_update>;
#define ll long long
#define pi pair<int,int>
#define vi vector<int>
#define pb push_back
#define all(a) a.begin(),a.end()
const int mxn = 500;
int arr[mxn+1];
ll dp[mxn*mxn+1];
short res[mxn*mxn+1];
void solve(){
int n; cin >> n;
dp[0] = 1;
int sum = 0;
for(int i = 1; i <= n; i++){
cin >> arr[i];
for(int j = sum; j >= 0; j--)
dp[j+arr[i]] += dp[j];
sum += arr[i];
}
if(sum%2 || dp[sum/2]==0){
cout << 0; return;
}
for(int i = 1; i <= n; i++){
for(int j = 0; j <= sum-arr[i]; j++)
dp[j+arr[i]] -= dp[j];
for(int j = (sum-arr[i])/2; j >= 0; j--){
if(dp[j] && dp[sum-arr[i]-j])
res[sum-arr[i]-2*j]++;
}
for(int j = sum-arr[i]; j >= 0; j--)
dp[j+arr[i]] += dp[j];
}
vector<int> vec;
for(int i = 1; i <= sum; i++) if(res[i]==n) vec.push_back(i);
cout << vec.size() << '\n';
for(auto x : vec) cout << x << ' ';
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
int t = 1;
// cin >> t;
while(t--){solve();}
}
