#include<bits/stdc++.h>
#define int long long
using namespace std;
int a[505];
int dp[500005];
int val[500005];
int can[500005];
int st;
int X=1000;
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;cin>>n;
int sum=0;
for(int i=1;i<=n;i++){
cin>>a[i];
sum+=a[i];
}
dp[0]=1;
for(int i=1;i<=n;i++){
for(int j=sum;j>=0;j--){
if(j-a[i]>=0)dp[j]+=dp[j-a[i]];
}
}
if(sum%2==1||dp[sum/2]==0){
cout<<"0\n";
return 0;
}
for(int i=0;i<=sum;i++)can[i]=0;
//for(int i=0;i<=sum;i++)cerr<<dp[i]<<" ";
//cerr<<"\n";
for(int i=1;i<=n;i++){
for(int j=0;j<=sum;j++)val[j]=dp[j];
for(int j=0;j<=sum;j++){
if(j-a[i]>=0)dp[j]-=dp[j-a[i]];
}
//cerr<<"i:"<<i<<"\n";
for(int j=0;j<=sum;j++){
if(dp[j]&&(sum-a[i]-2*j>=0)){
can[sum-a[i]-2*j]++;
//cerr<<"can:"<<sum-a[i]-2*j<<"\n";
}
}
for(int j=sum;j>=0;j--){
if(j-a[i]>=0)dp[j]+=dp[j-a[i]];
}
}
vector<int>ans;
for(int i=0;i<=sum;i++)if(can[i]==n)ans.push_back(i);
cout<<ans.size()<<"\n";
for(auto x:ans)cout<<x<<" ";
}
