#include <bits/stdc++.h>
const int size = 300000;
using namespace std;
int equal(double a, double b) {
  if (fabs(a - b) < 1e-6) return 1;
  return 0;
}
int main() {
  int f[size];
  int i;
  int tot;
  int n;
  while (~scanf("%d", &n)) {
    tot = 0;
    for (i = 1; i <= n; i++) {
      scanf("%d", &f[i]);
      tot += f[i];
    }
    queue<int> q;
    for (i = 1; i <= n; i++) {
      double a = f[i];
      double b = double(tot - f[i]) / (n - 1) * 1.0;
      if (equal(a, b)) q.push(i);
    }
    if (q.size() > 0) {
      printf("%d\n", q.size());
      while (!q.empty()) {
        printf("%d ", q.front());
        q.pop();
      }
      printf("\n");
    } else {
      printf("0");
    }
  }
  return 0;
}
