#include <bits/stdc++.h>
using namespace std;
#define fs first
#define ss second
#define endl '\n'
#define all(a) a.begin(), a.end()
#define print(a) \
for(auto x : a) \
cout << x << ' '; \
cout << endl;
#define printmp(a) \
for (auto x : a) \
cout << x.fs << ' ' << x.ss << endl;
void solve(){
int n, s = 0;
cin >> n;
vector<int> a(n);
bool juft = true, toq = true;
for(int i = 0; i < n; i ++)
cin >> a[i], s += a[i], juft &= (a[i] % 2 == 0), toq &= (a[i] % 2 == 1);
if(s % 2 == 1 or juft == toq){
cout << 0;
return;
}
vector<bitset<500>> dp(s + 1);
vector<bool> can(s + 1);
can[0] = true;
int s1 = 0;
for (int i = 0; i < n; i++)
{
s1 += a[i];
for (int j = s1; j >= a[i]; j--)
{
if (can[j - a[i]])
{
if (!can[j])
{
dp[j] = dp[j - a[i]];
dp[j][i] = 1;
}
else
dp[j] = dp[j] & dp[j - a[i]];
can[j] = true;
}
}
}
if(!can[s / 2]){
cout << 0;
return;
}
vector<int> ans;
for(int x = 0; x <= s; x ++){
bool flag = (s - a[0] + x) % 2 == 0;
for(int j = 0; j < n; j ++){
if(can[(s - a[j] + x) / 2] and !dp[(s - a[j] + x) / 2][j])
continue;
else{
flag = 0;
break;
}
}
if(flag)
ans.push_back(x);
}
cout << ans.size() << endl;
print(ans)
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
while(t --){
solve();
cout << endl;
}
}
