#include <bits/stdc++.h>
using namespace std;
class Fenwick {
 private:
  vector<int> arr;
  const int size;

 public:
  Fenwick(int n) : arr(n + 1), size(n) {
    for (int it = 0; it < arr.size(); ++it) arr[it] = 0;
  }
  void add(int v, int k) {
    for (; k <= size; k += (k) & (-k)) {
      arr[k] += v;
    }
  }
  int get(int k) {
    int total = 0;
    for (; k > 0; k -= (k) & (-k)) {
      total += arr[k];
    }
    return total;
  }
};
template <typename U>
class Comparator {
 public:
  bool operator()(const U lhs, const U rhs) { return true; }
};
int main() {
  int n;
  scanf("%d", &n);
  int first[n];
  int total = 0;
  for (int it = 0; it < n; ++it) {
    scanf("%d", &first[it]);
    total += first[it];
  }
  vector<int> ans;
  for (int it = 0; it < n; ++it) {
    if (((total - first[it]) % (n - 1) == 0) and
        ((total - first[it]) / (n - 1) == first[it]))
      ans.push_back(it);
  }
  printf("%d\n", ans.size());
  for (int it = 0; it < ans.size(); ++it) {
    if (it) printf(" ");
    printf("%d", ans[it] + 1);
  }
  printf("\n");
  return 0;
}
