#include <iostream>
using namespace std;
const int MAX_N = 500;
const int MOD = 1e9 + 7;
int a[MAX_N + 1], dp[MAX_N * MAX_N + 1], ways[MAX_N * MAX_N + 1], ways2[MAX_N * MAX_N + 1], cnt[MAX_N * MAX_N + 1], aux[MAX_N * MAX_N + 1];
int n;
void addSelf(int &a, int b) {
a += b;
if (a >= MOD) {
a -= MOD;
}
}
bool hentai(int pos) {
int s = 0;
for (int i = 1; i <= n; i++) {
if (i != pos) {
s += a[i];
}
}
if (pos == 0) {
dp[0] = true;
ways[0] = 1;
for (int i = 1; i <= n; i++) {
for (int j = s; j >= a[i]; j--) {
dp[j] |= dp[j - a[i]];
addSelf(ways[j], ways[j - a[i]]);
}
}
if (s % 2 == 0 && dp[s / 2]) {
return true;
} else {
return false;
}
} else {
for (int i = 0; i <= s + a[pos]; i++) {
ways2[i] = ways[i];
}
for (int i = a[pos]; i <= s + a[pos]; i++) {
addSelf(ways[i], -ways[i - a[pos]]);
}
for (int i = 0; i <= s / 2; i++) {
if (ways[i]) {
cnt[s - 2 * i]++;
}
}
for (int i = 0; i <= s + a[pos]; i++) {
aux[i] = ways[i];
}
for (int i = 0; i <= s + a[pos]; i++) {
ways[i] = ways2[i];
}
return true;
}
}
int main() {
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> a[i];
}
if (!hentai(0)) {
cout << "0\n";
return 0;
}
for (int i = 1; i <= n; i++) {
hentai(i);
}
int answer = 0;
for (int i = 0; i <= MAX_N * MAX_N; i++) {
if (cnt[i] == n) {
answer++;
}
}
cout << answer << "\n";
for (int i = 0; i <= MAX_N * MAX_N; i++) {
if (cnt[i] == n) {
cout << i << " ";
}
}
return 0;
}
