CF761E.Dasha and Puzzle

普及/提高-

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题目描述

Dasha decided to have a rest after solving the problem. She had been ready to start her favourite activity — origami, but remembered the puzzle that she could not solve.

The tree is a non-oriented connected graph without cycles. In particular, there always are n1n-1 edges in a tree with nn vertices.

The puzzle is to position the vertices at the points of the Cartesian plane with integral coordinates, so that the segments between the vertices connected by edges are parallel to the coordinate axes. Also, the intersection of segments is allowed only at their ends. Distinct vertices should be placed at different points.

Help Dasha to find any suitable way to position the tree vertices on the plane.

It is guaranteed that if it is possible to position the tree vertices on the plane without violating the condition which is given above, then you can do it by using points with integral coordinates which don't exceed 101810^{18} in absolute value.

输入格式

The first line contains single integer nn (1<=n<=30)(1<=n<=30) — the number of vertices in the tree.

Each of next n1n-1 lines contains two integers uiu_{i} , viv_{i} ( 1<=ui,vi<=n1<=u_{i},v_{i}<=n ) that mean that the ii -th edge of the tree connects vertices uiu_{i} and viv_{i} .

It is guaranteed that the described graph is a tree.

输出格式

If the puzzle doesn't have a solution then in the only line print "NO".

Otherwise, the first line should contain "YES". The next nn lines should contain the pair of integers xix_{i} , yiy_{i} (xi,yi<=1018)(|x_{i}|,|y_{i}|<=10^{18}) — the coordinates of the point which corresponds to the ii -th vertex of the tree.

If there are several solutions, print any of them.

输入输出样例

  • 输入#1

    7
    1 2
    1 3
    2 4
    2 5
    3 6
    3 7

    输出#1

    YES
    0 0
    1 0
    0 1
    2 0
    1 -1
    -1 1
    0 2
  • 输入#2

    6
    1 2
    2 3
    2 4
    2 5
    2 6
    

    输出#2

    NO
    
  • 输入#3

    4
    1 2
    2 3
    3 4

    输出#3

    YES
    3 3
    4 3
    5 3
    6 3

说明/提示

In the first sample one of the possible positions of tree is:

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