#include <bits/stdc++.h>
#define pb push_back
#define pf push_front
using namespace std;
#define F first
#define S second
typedef long long ll;
#define pii pair <int, int>
#define pll pair <ll, ll>
typedef long double ld;
const ll N = 250000 + 100, M = 4096 + 10, len = 315, inf = 1e18;
const ll mod = 1e9 + 7;
ll um(ll a, ll b){
return (1LL * a * b) % mod;
}
ll subr(ll a, ll b){
return ((1LL * a - b) % mod + mod) % mod;
}
int arr[N];
int main() {
int n, sm = 0;
cin >> n;
bool c1 = false, c2 = false;
for(int i = 1; i <= n; i++){
cin >> arr[i];
sm += arr[i];
if(arr[i] % 2 == 1) c1 = true;
else c2 = true;
}
bitset <250100> cur;
cur[0] = 1;
for(int i = 1; i <= n; i++){
cur |= (cur << arr[i]);
}
if(sm % 2 == 1 || cur[sm/2] == 0 || c1 + c2 == 2){
cout << 0;
return 0;
}
bitset <250100> ans;
for(int i = 1; i <= n; i++){
bitset <250100> b;
b[0] = 1;
for(int j = 1; j <= n; j++){
if(i == j) continue;
b |= (b << arr[j]);
}
if(i == 1) ans = (b >> ((sm - arr[i])/2));
else ans &= (b >> ((sm - arr[i])/2));
}
vector <int> vec;
for(int i = 1; i <= sm; i++){
if(ans[i]){
if(c1) vec.pb(i * 2 - 1);
else vec.pb(i * 2);
}
}
cout << (int)vec.size() << endl;
for(auto u : vec){
cout << u << " ";
}
return 0;
}
