#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
const int N = 510;
const int A = 510;
bitset<250069> sf[N], sv, ans, pr[N], even, odd;
int n, a[N];
signed main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int tt = 1;
//cin >> tt;
while (tt--) {
cin >> n;
sv[0] = 1;
for (int i = 1;i <= n;i++)
cin >> a[i], sv |= (sv << a[i]);
int s = accumulate(a + 1, a + n + 1, 0);
if (s % 2 == 1 || sv[s / 2] == 0) {
cout << '0';
return 0;
}
pr[0][0] = 1;
for (int i = 1;i <= n;i++)
pr[i] = pr[i - 1] | (pr[i - 1] << a[i]);
sf[n + 1][0] = 1;
for (int i = n;i >= 1;i--)
sf[i] = sf[i + 1] | (sf[i + 1] << a[i]);
even.set();
odd.set();
bitset<250069> cur;
for (int i = 1;i <= n;i++) {
if (i > n / 2) {
cur = pr[i - 1];
for (int j = i + 1;j <= n;j++)
cur |= (cur << a[j]);
}
else {
cur = sf[i + 1];
for (int j = i - 1;j > 0;j--)
cur |= (cur << a[j]);
}
int l = s - a[i];
if (l % 2 == 0) {
//j mora bude parno
even &= (cur >> (l / 2));
odd &= 0;
}
else {
odd &= (cur >> ((l + 1) / 2));
even &= 0;
}
}
cout << even.count() + odd.count() << '\n';
for (int i = 0;i < 250069;i++) {
if (even[i])
cout << 2 * i << ' ';
else if (odd[i])
cout << 2 * i + 1 << ' ';
}
}
return 0;
}
