#include<bits/stdc++.h>
using namespace std;
const int N = 505;
int dp[N*N];
const int EMPTY = INT_MAX;
int v[N];
bool good[N * N];
int main()
{
//freopen(".in","r",stdin);
ios::sync_with_stdio(false);
cin.tie(0),cout.tie(0);
int n;
cin>>n;
int sum = 0;
for(int i=1;i<=n;i++){
cin>>v[i];
sum += v[i];
}
for(int i=0; i< N*N; i++)
dp[i] = EMPTY, good[i] = true;
dp[0] = 0;
for(int i = 1; i<=n;i ++){
for(int val = N*N - 1 - v[i]; val >=0; val--){
if(dp[val] != EMPTY){
dp[val + v[i]] = min(dp[val + v[i]], i);
}
}
}
if(sum%2 == 1 || (dp[sum/2] == EMPTY)){
cout<<"0\n";
return 0;
}
for(int i = n; i >=1; i--){
for(int val = N*N -1; val >=0; val--){
if(dp[val] == i)
dp[val] = EMPTY;
}
if(i + 1 <= n){
for(int val = N*N -1 - v[i + 1]; val>=0; val--){
if(dp[val] != EMPTY){
dp[val + v[i + 1]] = min(dp[val + v[i + 1]], dp[val]);
}
}
}
for(int news = 1; news< N*N; news ++){
if(good[news] == false)
continue;
int newsum = sum - v[i] + news;
if(newsum %2 == 1 || (dp[newsum / 2] == EMPTY))
good[news] = false;
}
}
int goodval = 0;
for(int i=1; i<N*N; i++){
if(good[i] == true)
goodval++;
}
cout<<goodval<<"\n";
for(int i=1; i< N*N; i++){
if(good[i] == true){
cout<<i<<" ";
}
}
return 0;
}
