#include<bits/stdc++.h>
using namespace std;
#define int long long
#define in array<int, 2>
#define pb push_back
#define pob pop_back
#define INF (int)1e17
#define fast() ios_base::sync_with_stdio(false); cin.tie(NULL)
const int mod = 1e9+33;
const int MX = 2e5+5e4+10;
int dp[MX];
void add(int x)
{
for(int i = MX-1; i >= x; i--)
{
dp[i]+=dp[i-x];
dp[i]%=mod;
}
return;
}
void rem(int x)
{
for(int i = x; i < MX; i++)
{
dp[i]-=dp[i-x]; dp[i]+=mod;
dp[i]%=mod;
}
return;
}
int l[MX];
int r[MX];
int st;
void kill(int x)
{
if(x == st)
st = r[st];
else
{
r[l[x]] = r[x];
l[r[x]] = l[x];
}
}
signed main()
{
fast();
for(int i = 1; i < MX; i++)
{
l[i] = i-1;
r[i] = i+1;
}
r[0] = 1;
dp[0] = 1;
int n;
cin >> n;
int S = 0;
vector<int> a(n+1);
for(int i = 1; i <= n; i++)
{
cin >> a[i]; S+=a[i];
add(a[i]);
}
if(S%2 || (dp[S/2] == 0))
{
cout << "0\n";
return 0;
}
for(int i = 1; i <= n; i++)
{
rem(a[i]);
for(int V = st; V < MX; V = r[V])
{
int D = S+V-a[i];
if(D%2)
kill(V);
if(dp[(D/2)] || ((D >= 2*V) && ((dp[(D/2)-V]))))
continue;
kill(V);
}
add(a[i]);
}
vector<int> v;
for(int V = st; V < MX; V = r[V])
v.pb(V);
cout << v.size() << "\n";
for(int x: v)
cout << x << " ";
cout << "\n";
return 0;
}
