#include <bits/stdc++.h>
using namespace std;
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  os << '{';
  string sep;
  for (const auto &x : v) os << sep << x, sep = ", ";
  return os << '}';
}
template <typename T>
ostream &operator<<(ostream &os, const set<T> &v) {
  os << '{';
  string sep;
  for (const auto &x : v) os << sep << x, sep = ", ";
  return os << '}';
}
template <typename T, size_t size>
ostream &operator<<(ostream &os, const array<T, size> &arr) {
  os << '{';
  string sep;
  for (const auto &x : arr) os << sep << x, sep = ", ";
  return os << '}';
}
template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
  return os << '(' << p.first << ", " << p.second << ')';
}
template <typename A, typename B>
ostream &operator<<(ostream &os, const map<A, B> &v) {
  os << '{';
  string sep;
  for (const auto &x : v) os << sep << x, sep = ", ";
  return os << '}';
}
void dbg_out() { cerr << endl; }
template <typename Head, typename... Tail>
void dbg_out(Head H, Tail... T) {
  cerr << ' ' << H;
  dbg_out(T...);
}
mt19937 mt_rng(chrono::steady_clock::now().time_since_epoch().count());
long long rand(long long a, long long b) {
  return uniform_int_distribution<long long>(a, b)(mt_rng);
}
template <long long D, typename T>
struct vec : public vector<vec<D - 1, T>> {
  static_assert(D >= 1, "Dimensions invalid");
  template <typename... Args>
  vec(long long n = 0, Args... args)
      : vector<vec<D - 1, T>>(n, vec<D - 1, T>(args...)) {}
};
template <typename T>
struct vec<1, T> : public vector<T> {
  vec(long long n = 0, const T &val = T()) : vector<T>(n, val) {}
};
template <class T>
bool cmin(T &a, const T &b) {
  return b < a ? a = b, 1 : 0;
}
template <class T>
bool cmax(T &a, const T &b) {
  return a < b ? a = b, 1 : 0;
}
const long long N = 2e5 + 5, inf = 1e18;
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  long long n;
  cin >> n;
  vector<long long> a(n);
  long long sum = 0;
  for (auto &it : a) {
    cin >> it;
    sum += it;
  }
  vector<long long> ans;
  for (long long i = 0; i < n; i++) {
    long long rem = sum - a[i];
    if (rem % (n - 1) == 0 && (rem / (n - 1) == a[i])) {
      ans.push_back(i + 1);
    }
  }
  cout << (long long)(ans.size()) << "\n";
  for (long long &x : ans) cout << x << " ";
  cout << "\n";
}
