COEF - Coeficientes


The problem is to calculate the coefficients in expansion of polynomial (x1+x2+...+xk)n.

Input

The input will consist of a set of pairs of lines. The first line of the pair consists of two integers n and k separated with space (0 < n, k <13). This integers define the power of the polynomial and the amount of the variables. The second line in each pair consists of k non-negative integers n1, ..., nk, where n1+...+nk=n.

Output

For each input pair of lines the output line should consist one integer, the coefficient by the monomial x1n1x2n2...xknk in expansion of the polynomial (x1+x2+...+xk)n.

Example

Input:
2 2
1 1
2 12
1 0 0 0 0 0 0 0 0 0 1 0

Output:
2
2

hide comments
Ehor Nechiporenko: 2010-10-23 18:33:05

Can somebody to explain why I have recived SIGSEGV result in my solution?

Vinay Saini: 2010-10-23 05:32:06

AC ...

Last edit: 2011-09-07 14:03:44
Michael T: 2010-07-04 17:48:40

It seems there're blank lines in the input. Cost me few nzecs.

Last edit: 2010-07-05 20:11:37

Added by:Coach UTN FRSF
Date:2010-06-02
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: NODEJS OBJC PERL6 SQLITE VB.NET
Resource:http://uva.onlinejudge.org/external/101/10105.html