#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define lft(x) x * 2
#define rgt(x) x * 2 + 1
#define tm hui_pizda
#define ft first
#define sd second
#define pb push_back
#define pf push_front
#define sz size()
#define cnt continue
#define m_p make_pair
#define fr(i, l, r) for(int i = l; i <= r; ++ i)
#define rf(i, r, l) for(int i = r; i >= l; -- i)
#define all(x) x.begin(), x.end()
#pragma GCC optimize(-O3)
#pragma GCC optimize(Ofast)
#pragma GCC optimize("unroll-loops")
using namespace __gnu_pbds;
using namespace std;
template <typename T>
using _set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
typedef long double ld;
typedef pair <ll, ll> pll;
typedef pair <int, int> pii;
typedef vector <int> vi;
typedef vector <ll> vl;
typedef vector <pii> vpi;
typedef vector <pll> vpl;
mt19937_64 rnd(time(NULL));
const ll N = 1e6 + 10;
const ll mtrxN = 10;
const ll oo = 1e18 + 10;
const ll B = 500;
const ll mod = 1e9 + 7;
struct mtrx{
ll m[mtrxN][mtrxN] = {};
};
mtrx mtrx_mult(mtrx a, mtrx b){
mtrx c;
fr(i, 0, mtrxN - 1){
fr(j, 0, mtrxN - 1){
ll sum = 0;
fr(x, 0, mtrxN - 1){
sum += a.m[i][x] * b.m[x][j];
sum %= mod;
}
c.m[i][j] = sum;
}
}
return c;
}
mtrx mtrx_pow(mtrx a, ll n){
mtrx res;
fr(i, 0, mtrxN - 1)fr(j, 0, mtrxN - 1)res.m[i][j] = a.m[i][j];
n --;
while(n){
if(n&1)res = mtrx_mult(res, a);
a = mtrx_mult(a, a);
n >>= 1;
}
return res;
}
ll _pow(ll a, ll n){
ll r = 1;
while(n){
if(n&1)r = r * a % mod;
a = a * a % mod;
n >>= 1;
}
return r;
}
ll div(ll x, ll y, ll md){
return x * _pow(y, md - 2) % md;
}
ll a[N];
ll n, NN;
vector <ll> calc(ll x){
vector <vl> dp;
dp.resize(n + 1);
fr(i, 0, n)dp[i].resize(2 * NN + 1);
dp[0][NN] = 1;
fr(i, 1, n){
if(i != x){
fr(j, 0, 2 * NN){
if(j + a[i] <= 2 * NN)dp[i][j + a[i]] |= dp[i - 1][j];
if(j - a[i] >= 0)dp[i][j - a[i]] |= dp[i - 1][j];
}
} else dp[i] = dp[i - 1];
}
return dp[n];
}
int main(){
ios_base::sync_with_stdio(0), cin.tie(0);
NN = 10000;
//NN = 10;
cin >> n;
fr(i, 1, n)cin >> a[i];
vl ans(2 * NN + 1, 1);
fr(i, 0, n){
vl now = calc(i);
if(i == 0){
if(!now[NN])return cout << 0, 0;
else cnt;
}
// cout << "i: " << i << endl;
// fr(j, 0, 2 * NN)
// cout << j - NN << ":" << now[j] << ' ';
// cout << endl;
fr(j, 0, 2 * NN)ans[j] &= now[j];
}
set <ll> ra;
fr(i, 0, 2 * NN)
if(ans[i])ra.insert(abs(i - NN));
cout << ra.sz << endl;
for(auto i : ra)cout << i << ' ';
cout << endl;
return 0;
}
/*
*/
