Problem: 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.

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Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
vector<int> adj[200005];
int head, tail;
int prnt[200005], deg[200005];
bool ok = true;
void dfs(int u, int pre) {
  if (pre != 0) {
    deg[u] = 1;
    deg[pre]++;
  }
  for (int i = 0; i < adj[u].size(); i++) {
    int v = adj[u][i];
    if (v != pre) dfs(v, u);
  }
  if (deg[u] & 1) {
    prnt[tail--] = u;
    if (pre == 0) {
      ok = false;
    }
  } else {
    prnt[head++] = u;
    deg[pre]--;
  }
}
int main() {
  int n;
  scanf("%d", &n);
  int root;
  for (int i = 1; i <= n; i++) {
    int v;
    scanf("%d", &v);
    if (v != 0)
      adj[v].push_back(i);
    else
      root = i;
  }
  memset(deg, 0, sizeof deg);
  head = 1, tail = n;
  dfs(root, 0);
  if (ok) {
    cout << "YES" << endl;
    for (int i = 1; i <= n; i++) cout << prnt[i] << endl;
  } else {
    cout << "NO" << endl;
  }
}