#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long
#define ld long double
// 217
// 44
using namespace std;
const int MOD = (int) 1e9 + 7;
const int MAXN = 500;
int arr[MAXN + 1];
int dp[MAXN * MAXN + 1];
inline void mod(int &x) {
if(x >= MOD)
x -= MOD;
}
int fr[MAXN * MAXN + 1];
int main() {
//ifstream cin("A.in");
//ofstream cout("A.out");
int i, j, n;
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
cin >> n;
dp[0] = 1;
int sum = 0;
for(i = 1; i <= n; i++) {
cin >> arr[i];
for(j = sum; j >= 0; j--) {
dp[j + arr[i]] += dp[j];
mod(dp[j + arr[i]]);
}
sum += arr[i];
}
if(dp[sum / 2] == 0) {
cout << 0;
return 0;
}
for(i = n; i >= 1; i--) {
for(j = arr[i]; j <= sum; j++) {
dp[j] -= dp[j - arr[i]] - MOD;
mod(dp[j]);
}
if(i < n) {
for(j = sum; j >= arr[i + 1]; j--) {
dp[j] += dp[j - arr[i + 1]];
mod(dp[j]);
}
}
for(j = 0; j <= sum; j++) {
if(dp[j] > 0) {
int x = 2 * j - sum + arr[i];
if(x >= 0 && x <= sum) {
fr[x]++;
}
}
}
}
int ans = 0;
for(i = 1; i <= sum; i++) {
if(fr[i] == n) {
ans++;
}
}
cout << ans << "\n";
for(i = 0; i <= sum; i++) {
if(fr[i] == n) {
cout << i << " ";
}
}
//cin.close();
//cout.close();
return 0;
}
