【英文原题】

The banquet hall of Computer Scientists' Palace has a rectangular form of the size M x N (1<=M<=9, 1<=N<=9). It is necessary to lay hardwood floors in the hall. There are wood pieces of two forms:

1) rectangles (2x1)

2) corners (squares 2x2 without one 1x1 square)

You have to determine X - the number of ways to cover the banquet hall.

Remarks. The number of pieces is large enough. It is not allowed to leave empty places, or to cover any part of a surface twice, or to saw pieces.

【题目描述】

给出n*m(1≤n、m≤9)的方格棋盘，用1*2 的矩形的骨牌和L 形的(2*2 的去

掉一个角)骨牌不重叠地覆盖，求覆盖满的方案数。

【输入格式】

输入一行两个正整数，即n,m

【输出格式】

输出一行一个正整数，即方案总数

【样例输入】

2 3

【样例输出】

5

【来源】

Author: Herman "Smash" Narkaytis, Paul "Stingray" Komkoff

Resource: 5th Southern Subregional Contest. Saratov 2002

SGU 131 Hardwood floor