HMT2 - How Many Trees 2

lqp18_31 count unrooted unlabeled trees with N nodes one by one.

But the number is so large that he is afraid that he will never stop counting.

So he asks you to tell him the number of unrooted unlabeled trees with N nodes modulo 10^9+7.

Input

One line containing one integer N. (1 <= N <= 1000)

Output

One line containing the number of unrooted unlabeled trees with N nodes modulo 10^9+7

Example

Input:
10

Output:
106

Added by:刘启鹏
Date:2010-05-18
Time limit:0.100s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: NODEJS OBJC PERL6 SQLITE VB.NET

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2010-07-20 01:33:22 ymGXX
PT07D
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