#include<bits/stdc++.h>
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
#define el '\n'
#define fi first
#define sc second
//#define int ll
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
const int mod=1e9+7;
const int N=511;
int n, a[N], sum;
bitset<N*N> bs, cur, s1, s2, pf1[N], pf2[N];
void sol()
{
cin >> n;
for(int i=1;i<=n;i++) cin >> a[i];
bs&=0;
bs[0]=1;
for(int i=1;i<=n;i++)
{
bs|=bs<<(a[i]);
sum+=a[i];
}
if(sum&1 || bs[sum/2]==0)
{
cout << 0 << el;
return;
}
pf1[0][0]=1;
pf2[n+1][0]=1;
for(int i=1;i<=n;i++) pf1[i]=pf1[i-1]|(pf1[i-1]<<a[i]);
for(int i=n;i>=1;i--) pf2[i]=pf2[i+1]|(pf2[i+1]<<a[i]);
int ch1=1, ch2=1;
s1.set();
s2.set();
s2[0]=0;
for(int i=1;i<=n;i++)
{
if(i<=n/2)
{
cur=pf2[i+1];
for(int j=i-1;j>=1;j--) cur|=(cur<<(a[j]));
}
else
{
cur=pf1[i-1];
for(int j=i+1;j<=n;j++) cur|=(cur<<(a[j]));
}
int ss=sum-a[i];
if(ss%2==0)
{
s2&=(cur>>(ss/2));
if(ch1)
{
s1&=0;
ch1=0;
}
}
else
{
s1&=(cur>>(ss/2+1));
if(ch2)
{
s2&=0;
ch2=0;
}
}
}
cout << s1.count()+s2.count() << el;
for(int i=0;i<N*N;i++)
{
if(s2[i]) cout << i*2 << el;
if(s1[i]) cout << i*2+1 << el;
}
}
signed main()
{
// freopen("divisor.INP", "r", stdin);
// freopen("divisor.OUT", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);
int t=1;
//cin >> t;
while(t--)
{
sol();
}
}
