#include <iostream>
using namespace std;
const int N = 505, M = N * N, mod = 1e9 + 7;
int Ws[M], fav[M], Ans, k, n, a[N], sm;
void Add(int &A, int b){
A += b;
if (A >= mod)
A -= mod;
}
int main(){
Ws[0] = 1;
cin>>n;
for (int i=1, vl;i<=n;i++){
cin>>vl, a[vl]++;
sm += vl;
for (int j=M-1;j>=vl;j--)
Add(Ws[j], Ws[j - vl]);
}
if (sm % 2 == 0 and Ws[sm / 2] != 0)
k = 1;
for (int i=1;i<N;i++){
if (a[i] == 0)
continue;
for (int j=i;j<M;j++)
Add(Ws[j], mod - Ws[j - i]);
for (int j=1;j<M;j++){
int nSum = sm - i + j, mid = nSum / 2;
if (nSum % 2 == 0 and Ws[mid] + (mid - j >= 0 ? Ws[mid - j] : 0) != 0)
fav[j] += a[i];
}
for (int j=M-1;j>=i;j--)
Add(Ws[j], Ws[j - i]);
}
for (int j=1;j<M;j++){
if (k == 1 and fav[j] == n)
Ans++;
}
cout<<Ans<<'\n';
for (int j=1;j<M;j++){
if (k == 1 and fav[j] == n)
cout<<j<<' ';
}
cout<<'\n';
}
