#include <bits/stdc++.h>
#ifdef DEBUG
#include "debug.hpp"
#endif
using namespace std;
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define traverse(c, it) for(auto it = (c).begin(); it != (c).end(); ++it)
#define rep(i, N) for(int i = 0; i < (N); ++i)
#define rrep(i, N) for(int i = (N) - 1; i >= 0; --i)
#define rep1(i, N) for(int i = 1; i <= (N); ++i)
#define rep2(i, s, e) for(int i = (s); i <= (e); ++i)
#ifdef DEBUG
#define debug(x...) { \
++dbg::depth; \
string dbg_vals = dbg::to_string(x); \
--dbg::depth; \
dbg::fprint(__func__, __LINE__, #x, dbg_vals); \
}
#define light_debug(x) { \
dbg::light = true; \
dbg::dout << __func__ << ":" << __LINE__; \
dbg::dout << " " << #x << " = " << x << endl; \
dbg::light = false; \
}
#else
#define debug(x...) 42
#define light_debug(x) 42
#endif
using ll = long long;
template<typename T>
inline T& ckmin(T& a, T b) { return a = a > b ? b : a; }
template<typename T>
inline T& ckmax(T& a, T b) { return a = a < b ? b : a; }
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int n; cin >> n;
vector<int> a(n); rep(i, n) cin >> a[i];
int s{accumulate(all(a), 0)};
vector<long long> ways(s + 1);
ways[0] = 1;
auto add = [&](int x) {
rrep(i, int(ways.size()))
if(i - x >= 0) ways[i] += ways[i - x];
};
auto remove = [&](int x) {
rep(i, int(ways.size()))
if(i - x >= 0) ways[i] -= ways[i - x];
};
rep(i, n) add(a[i]);
debug(ways);
if(s % 2 != 0 || ways[s / 2] == 0)
return cout << 0 << '\n', 0;
vector<int> c(s + 1);
vector<bool> b(s + 1);
rep(i, n) {
remove(a[i]);
rep(x, int(ways.size())) {
if(ways[x] == 0) continue;
b[abs(s - a[i] - 2 * x)] = true;
}
rep(x, int(c.size()))
if(b[x]) ++c[x], b[x] = false;
debug(i, ways);
add(a[i]);
}
cout << count_if(all(c), [&](int x) { return x == n; }) << '\n';
rep(i, int(c.size())) if(c[i] == n) cout << i << ' ';
cout << '\n';
#ifdef DEBUG
dbg::dout << "\nExecution time: "
<< clock() * 1000 / CLOCKS_PER_SEC
<< "ms" << endl;
#endif
return 0;
}
