#include <bits/stdc++.h>
using namespace std;
int a[200005];
int main() {
  int n;
  scanf("%d", &n);
  int sum = 0;
  for (int i = 1; i <= n; ++i) {
    scanf("%d", &a[i]);
    sum += a[i];
  }
  vector<int> ans;
  for (int i = 1; i <= n; ++i) {
    if ((sum - a[i]) % (n - 1) == 0 && (sum - a[i]) / (n - 1) == a[i]) {
      ans.push_back(i);
    }
  }
  printf("%d\n", (int)ans.size());
  for (auto p : ans) {
    printf("%d\n", p);
  }
}
