#include <bits/stdc++.h>
using namespace std;
#define int long long
const int NM = 500, MOD = 1e15+7;
int N, a[NM+5], sum = 0, dp[NM*NM+5], dp0[NM*NM+5], K = 0;
bool ok[NM*NM+5];
void add(int x){
for (int i = NM*NM; i >= x; i--)
dp[i] = (dp[i]+dp[i-x])%MOD;
}
void remove(int x){
for (int i = x; i <= NM*NM; i++)
dp[i] = (dp[i]+MOD-dp[i-x])%MOD;
}
void solve(int t){
for (int i = 0; i <= NM*NM; i++) dp[i] = dp0[i];
remove(a[t]);
for (int i = 1; i <= NM*NM; i++)
if ((sum-a[t]+i)%2 != 0 || (sum-a[t]+i)/2-i < 0 || !dp[(sum-a[t]+i)/2-i]) ok[i] = 0;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> N;
dp[0] = 1;
for (int i = 1; i <= N; i++){
cin >> a[i];
sum += a[i];
add(a[i]);
}
if (sum%2 != 0 || !dp[sum/2]){
cout << "0\n";
return 0;
}
for (int i = 0; i <= NM*NM; i++){
dp0[i] = dp[i];
ok[i] = 1;
}
for (int i = 1; i <= N; i++)
solve(i);
for (int i = 1; i <= NM*NM; i++) K += ok[i];
cout << K << '\n';
for (int i = 1; i <= NM*NM; i++)
if (ok[i]) cout << i << ' ';
return 0;
}
