#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <bitset>
#include <vector>
typedef long long llong;
const int MAXS = 250000 + 10;
const int MAXN = 500 + 10;
const int MOD = 1e9 + 13;
int n;
int a[MAXN];
int dp[MAXS];
int copy[MAXS];
int cnt[MAXS];
void solve()
{
int sum = 0;
dp[0] = 1;
for (int i = 1 ; i <= n ; ++i)
{
sum += a[i];
for (int j = MAXS - 1 ; j >= a[i] ; --j)
{
dp[j] += dp[j - a[i]];
if (dp[j] >= MOD) dp[j] -= MOD;
}
}
if ((sum & 1) || (!dp[sum / 2]))
{
std::cout << "0\n\n";
return;
}
for (int i = 1 ; i <= n ; ++i)
{
for (int j = 1 ; j < MAXS ; ++j)
{
copy[j] = dp[j];
}
for (int j = 0 ; j + a[i] < MAXS ; ++j)
{
dp[j + a[i]] -= dp[j];
if (dp[j + a[i]] < 0)
{
dp[j + a[i]] += MOD;
}
}
for (int j = 0 ; j < MAXS && sum - a[i] - 2 * j > 0 ; ++j)
{
if (dp[j] != 0)
{
cnt[sum - a[i] - 2 * j]++;
}
}
for (int j = 1 ; j < MAXS ; ++j)
{
dp[j] = copy[j];
}
}
int count = 0;
for (int i = 1 ; i < MAXS ; ++i)
{
count += (cnt[i] == n);
}
std::cout << count << '\n';
for (int i = 1 ; i < MAXS ; ++i)
{
if (cnt[i] == n)
{
std::cout << i << ' ';
}
}
std::cout << '\n';
}
void input()
{
std::cin >> n;
for (int i = 1 ; i <= n ; ++i)
{
std::cin >> a[i];
}
}
void fastIOI()
{
std::ios_base :: sync_with_stdio(0);
std::cout.tie(nullptr);
std::cin.tie(nullptr);
}
int main()
{
fastIOI();
input();
solve();
return 0;
}
