You are given a tree (a graph with n vertices and n - 1 edges in which it's possible to reach any vertex from any other vertex using only its edges).

A vertex can be destroyed if this vertex has even degree. If you destroy a vertex, all edges connected to it are also deleted.

Destroy all vertices in the given tree or determine that it is impossible.

Input

The first line contains integer n (1 ≤ n ≤ 2·105) — number of vertices in a tree.

The second line contains n integers p1, p2, ..., pn (0 ≤ pi ≤ n). If pi ≠ 0 there is an edge between vertices i and pi. It is guaranteed that the given graph is a tree.

Output

If it's possible to destroy all vertices, print "YES" (without quotes), otherwise print "NO" (without quotes).

If it's possible to destroy all vertices, in the next n lines print the indices of the vertices in order you destroy them. If there are multiple correct answers, print any.

Examples

Input

5
0 1 2 1 2


Output

YES
1
2
3
5
4


Input

4
0 1 2 3


Output

NO

Note

In the first example at first you have to remove the vertex with index 1 (after that, the edges (1, 2) and (1, 4) are removed), then the vertex with index 2 (and edges (2, 3) and (2, 5) are removed). After that there are no edges in the tree, so you can remove remaining vertices in any order.

<image>
#include <bits/stdc++.h>
using namespace std;
const int N = 200000 + 5;
int deg[N];
vector<int> G[N];
bool done[N];
void split(int u, int f) {
  cout << u << '\n';
  done[u] = true;
  for (int v : G[u]) deg[v] ^= 1;
  for (int v : G[u])
    if (v != f and !done[v]) {
      if (!deg[v]) split(v, u);
    }
}
void dfs(int u, int f) {
  for (int v : G[u])
    if (v != f) {
      dfs(v, u);
    }
  if (!deg[u]) split(u, f);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    int x;
    cin >> x;
    if (x == 0) continue;
    deg[x] ^= 1;
    deg[i] ^= 1;
    G[x].push_back(i);
    G[i].push_back(x);
  }
  if (n % 2 == 0)
    cout << "NO\n";
  else
    cout << "YES\n", dfs(1, 1);
  return 0;
}
