output_description: 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.
  
  * * *
input_description: 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}
attempt: print(-1)
  
problem_description: 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.
samples: [{"input": "6\n    1 2\n    1 3\n    1 4\n    1 5\n    5 6", "output": "1 2 4 5 3 6\n    \n\nIf the permutation (1, 2, 4, 5, 3, 6) is used to generate a tree, it looks as\nfollows:\n\n![](https://img.atcoder.jp/arc095/db000b879402aed649a1516620eb1e21.png)\n\nThis is isomorphic to the given graph.\n\n* * *"}, {"input": "6\n    1 2\n    2 3\n    3 4\n    1 5\n    5 6", "output": "1 2 3 4 5 6\n    \n\n* * *"}, {"input": "15\n    1 2\n    1 3\n    2 4\n    2 5\n    3 6\n    3 7\n    4 8\n    4 9\n    5 10\n    5 11\n    6 12\n    6 13\n    7 14\n    7 15", "output": "-1"}]