#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  float sum = 0;
  cin >> n;
  int k[n], count = 0;
  float a[n];
  for (int i = 1; i <= n; i++) cin >> a[i];
  for (int i = 1; i <= n; i++) sum += a[i];
  for (int i = 1; i <= n; i++) {
    if ((sum - a[i]) / (n - 1) == a[i]) {
      count++;
      k[count] = i;
    }
  }
  if (count > 0) {
    cout << count << endl;
    for (long long int i = 1; i <= count; i++) cout << k[i] << " ";
  } else
    cout << 0;
  return 0;
}
