#include <cstdio>
#include <stdio.h>
#include <stdbool.h>
#include <iostream>
#include <map>
#include <vector>
#include <climits>
#include <stack>
#include <string>
#include <queue>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cmath>
#include <cctype>
#include <bitset>
#include <iomanip>
#include <cstring>
#include <numeric>
#include <cassert>
using namespace std;
#define int long long
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define fi first
#define se second
int32_t main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, k=0;
cin>>n;
vector<int> vect(n);
for (int i=0; i<n; ++i)cin>>vect[i], k+=vect[i];
vector<int> dp(k+1, 0), cc(k+1, 0);
dp[0]=1;
for (int i=0; i<n; ++i)for (int j=k; j>=vect[i]; --j)dp[j]+=dp[j-vect[i]];
if (k%2||!dp[k/2]){
cout<<0;
return 0;
}
for (int i=0; i<n; ++i){
for (int j=vect[i]; j<=k; ++j)dp[j]-=dp[j-vect[i]];
k-=vect[i];
for (int j=0; j<=k/2; ++j)if (dp[j])++cc[k-2*j];
k+=vect[i];
for (int j=k; j>=vect[i]; --j)dp[j]+=dp[j-vect[i]];
}
vector<int> ans;
for (int i=0; i<=k; ++i)if (cc[i]==n)ans.pb(i);
cout<<ans.size()<<"\n";
for (auto a:ans)cout<<a<<" ";
}
