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[1000000], ans;
int n, u, v;
int vis[1000000], par[1000000];
void take(int cur) {
  ans.push_back(cur);
  vis[cur] = 1;
  for (int i = 0; i < adj[cur].size(); ++i)
    if (!vis[adj[cur][i]]) take(adj[cur][i]);
}
void dfs(int cur) {
  int deg = 0;
  for (int i = 0; i < adj[cur].size(); ++i) {
    dfs(adj[cur][i]);
    if (!vis[adj[cur][i]]) deg++;
  }
  if (par[cur]) deg++;
  if (!(deg & 1) && cur) take(cur);
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    scanf("%d", &par[i]);
    adj[par[i]].push_back(i);
  }
  dfs(0);
  if (ans.size() < n)
    printf("NO\n");
  else {
    printf("YES\n");
    for (int i = 0; i < ans.size(); ++i) printf("%d\n", ans[i]);
  }
  return 0;
}