#include<bits/stdc++.h>
using namespace std;
const int MAXN=512;
int n,a[MAXN],sum;
struct node
{
vector<int>vals;
bitset<MAXN*MAXN>possible;
};
node tree[4*MAXN];
bitset<MAXN*MAXN>without[MAXN];
void update(int l,int r,int idx,int ql,int qr,int val)
{
if(l>qr)return;
if(r<ql)return;
if(l>=ql&&r<=qr)
{
tree[idx].vals.push_back(val);
return;
}
int mid=(l+r)/2;
update(l,mid,idx*2,ql,qr,val);
update(mid+1,r,idx*2+1,ql,qr,val);
}
void build(int l,int r,int idx)
{
tree[idx].possible[0]=1;
for(auto xd:tree[idx].vals)
{
tree[idx].possible=tree[idx].possible|(tree[idx].possible<<xd);
}
if(l==r)
{
without[l]=tree[idx].possible;
return;
}
int mid=(l+r)/2;
tree[idx*2].possible=tree[idx].possible;
tree[idx*2+1].possible=tree[idx].possible;
build(l,mid,idx*2);
build(mid+1,r,idx*2+1);
}
int main()
{
cin>>n;
for(int i=1;i<=n;i++){cin>>a[i];sum+=a[i];}
if(sum%2==1)
{
cout<<"0\n";
return 0;
}
for(int i=1;i<=n;i++)
{
update(1,n+1,1,1,i-1,a[i]);
update(1,n+1,1,i+1,n+1,a[i]);
}
build(1,n+1,1);
if(without[n+1][sum/2]==0)
{
cout<<"0\n";
return 0;
}
//cout<<"?\n";
vector<int>ans;
for(int cand=1;cand<=sum;cand++)
{
bool ok=1;
for(int i=1;i<=n;i++)
{
int sum1=sum+cand-a[i];
if(sum1%2!=0)
{
ok=0;break;
}
if(without[i][sum1/2]==0)
{
ok=0;break;
}
}
if(ok)ans.push_back(cand);
}
cout<<ans.size()<<endl;
for(auto xd:ans)
{
cout<<xd<<" ";
}
cout<<endl;
return 0;
}
