#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'; }