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Problem 1715 Ball and Box

Accept: 146    Submit: 364
Time Limit: 1000 mSec    Memory Limit : 32768 KB

Problem Description

CDGG has r different boxes and n different balls.He want to put the n balls into the r boxes,and it is not allow to left empty box.How many ways can CDGG put the n balls into the r boxes?

Input

The input consists of several test cases. For each case,the only line contains two integer n and r,indicates the number of balls and the number of boxes.(0<=n,r<=10)

Output

For each case,output a line contain a integer,indicates the answer.

Sample Input

3 2

Sample Output

6

Source

FZU 2009 Summer Training Qualification -- Hero Revival 1

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