Problem Statement
Takahashi has an ability to generate a tree using a permutation $(p_1,p_2,...,p_n)$ of $(1,2,...,n)$, in the following process:
First, prepare Vertex $1$, Vertex $2$, ..., Vertex $N$. For each $i=1,2,...,n$, perform the following operation:
- If
$p_i = 1$, do nothing. - If
$p_i \neq 1$, let$j'$be the largest$j$such that$p_j < p_i$. Span an edge between Vertex$i$and Vertex$j'$.
Takahashi is trying to make his favorite tree with this ability. His favorite tree has $n$ vertices from Vertex $1$ through Vertex $n$, and its $i$-th edge connects Vertex $v_i$ and $w_i$. Determine if he can make a tree isomorphic to his favorite tree by using a proper permutation. If he can do so, find the lexicographically smallest such permutation.
Note
For the definition of isomorphism of trees, see wikipedia. Intuitively, two trees are isomorphic when they are the "same" if we disregard the indices of their vertices.
Constraints
$2 \leq n \leq 10^5$$1 \leq v_i, w_i \leq n$- The given graph is a tree.
Input
Input is given from Standard Input in the following format:
n
v_1 w_1
v_2 w_2
:
v_{n-1} w_{n-1}
Output
If there is no permutation that can generate a tree isomorphic to Takahashi's favorite tree, print -1. If it exists, print the lexicographically smallest such permutation, with spaces in between.
样例
6
1 2
1 3
1 4
1 5
5 6
1 2 4 5 3 6
6
1 2
2 3
3 4
1 5
5 6
1 2 3 4 5 6
15
1 2
1 3
2 4
2 5
3 6
3 7
4 8
4 9
5 10
5 11
6 12
6 13
7 14
7 15
-1
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