#include <bits/stdc++.h>
#define int long long
#define boost ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
using namespace std;
const int N = (500*500)+1;
const int inf = 1e9;
const int mod=1e9+7;
struct edge{
int x,y,c;
};
vector<int>v;
int dp[N];
vector<int>v1;
int ok[N];
signed main(){
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
boost
int n;
cin>>n;
v.push_back(0);
int sum=0;
for(int i=1;i<=n;i++){
int x;
cin>>x;
sum+=x;
v.push_back(x);
}
dp[0]=1;
for(int i=1;i<=n;i++){
for(int j=sum;j>=v[i];j--){
dp[j]=(dp[j]+dp[j-v[i]])%mod;
}
}
if(sum%2==1||dp[sum/2]==0){
cout<<0;
return 0;
}
int cnt=sum;
for(int i=1;i<=n;i++){
for(int j=v[i];j<=sum;j++){
dp[j]=(dp[j]-dp[j-v[i]]+mod)%mod;
}
for(int j=1;j<=sum;j++){
if((sum-v[i]+j)%2==1||dp[(sum-v[i]+j)/2]==0){
if(ok[j]==0){
ok[j]=1;
cnt--;
}
}
}
for(int j=sum;j>=v[i];j--){
dp[j]=(dp[j]+dp[j-v[i]])%mod;
}
}
cout<<cnt<<"\n";
for(int i=1;i<=sum;i++){
if(ok[i]==0){
cout<<i<<" ";
}
}
}
