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;
const int N = 2e5 + 10;
vector<int> G[N];
stack<int> S;
int in[N];
int pre[N];
int fa[N];
int dfss;
void dfs(int u, int fas) {
  pre[u] = dfss++;
  fa[u] = fas;
  for (int i = 0; i < G[u].size(); i++) {
    int v = G[u][i];
    if (v == fas) continue;
    dfs(v, u);
  }
  if (in[u] % 2 == 1) S.push(u);
  if (in[u] % 2 == 0) {
    printf("%d\n", u);
    in[fa[u]]--;
    while (!S.empty()) {
      int s = S.top();
      if (pre[s] < pre[u]) break;
      S.pop();
      printf("%d\n", s);
      in[fa[s]]--;
    }
  }
}
int main() {
  int n;
  scanf("%d", &n);
  int x;
  dfss = 0;
  memset(in, 0, sizeof(in));
  for (int i = 1; i <= n; i++) {
    scanf("%d", &x);
    if (x == 0) continue;
    in[x]++;
    in[i]++;
    G[i].push_back(x);
    G[x].push_back(i);
  }
  if (n % 2 == 0) {
    puts("NO");
    return 0;
  }
  printf("YES\n");
  dfs(1, 0);
  return 0;
}