#include <bits/stdc++.h>
using namespace std;
int n, a[5000005];
int main() {
  long double sum = 0;
  vector<int> q;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    sum += a[i];
  }
  for (int i = 0; i < n; i++) {
    if ((sum - a[i]) / (n - 1) == a[i]) {
      q.push_back(i + 1);
    }
  }
  cout << q.size() << endl;
  for (int i = 0; i < q.size(); i++) cout << q[i] << " ";
}
