#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define all(v) begin(v), end(v)
#define pi pair<int, int>
#define vi vector<int>
using namespace std;
const int N = 5e2;
int n, a[N+2];
int cnt[N*N+2];
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n;
for(int i = 1; i <= n; i++) cin >> a[i];
int su = accumulate(a+1, a+n+1, 0);
int mx = *max_element(a+1, a+n+1);
bitset<N*N> dp;
dp.reset();
dp[0] = 1;
for(int i = 1; i <= n; i++) dp |= (dp << a[i]);
if(su % 2 != 0 || !dp[su/2]){
cout << 0;
return 0;
}
if(su - mx < 1){
cout << 0;
return 0;
}
for(int i = 1; i <= n; i++){
bitset<N*N> dp2;
dp2.reset();
dp2[0] = 1;
for(int j = 1; j <= n; j++)
if(i != j) dp2 |= (dp2 << a[j]);
vector<bool> ck(su-mx+1, 0);
for(int j = 0; j <= su - a[i]; j++){
if(dp2[j]){
int x = abs(su-a[i]-2*j);
if(x >= 1 && x <= su - mx){
if(!ck[x]){
ck[x] = true;
cnt[x]++;
}
}
}
}
}
vector<int> ans;
for(int i = 1; i <= N*N; i++){
if(cnt[i] == n) ans.push_back(i);
}
cout << ans.size() << "\n";
for(auto x:ans) cout << x << " ";
return 0;
}
