#include <bits/stdc++.h>
using namespace std;
int a[500005];
long long s[500005];
int main() {
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i];
  sort(a + 1, a + n + 1);
  for (int i = 1; i <= n; i++) s[i] = s[i - 1] + a[i];
  long long l = -1, r = n + 2;
  for (int k = 1, j = 0; k <= n; k++) {
    while (j < n && a[j + 1] < k) j++;
    long long t = s[n] - s[n - k] - (long long)k * (k - 1) - s[min(n - k, j)] -
                  (long long)k * (n - k - min(n - k, j));
    l = max(l, t);
    r = min(r, -t + a[n - k + 1] + min(a[n - k + 1], k));
  }
  if (r < l) {
    puts("-1");
  } else {
    for (int i = l; i <= r; i++)
      if (!(s[n] + i & 1)) cout << i << ' ';
  }
  return 0;
}
