#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  long long n;
  cin >> n;
  vector<long long> a(n);
  long long sum = 0;
  for (int i = 0; i < n; i++) cin >> a[i], sum += a[i];
  vector<long long> res;
  for (int i = 0; i < n; i++) {
    long long tmp = sum - a[i];
    if (tmp / (n - 1) == a[i] && tmp % (n - 1) == 0) {
      res.push_back(i + 1);
    }
  }
  cout << res.size() << '\n';
  for (auto x : res) cout << x << " ";
  cout << '\n';
  return 0;
}
