p2663_Tri Tilling(矩陣乘法應用)

Tri Tiling

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 4294		Accepted: 2222

Description

In how many ways can you tile a 3xn rectangle with 2x1 dominoes?
Here is a sample tiling of a 3x12 rectangle.

Input

Input consists of several test cases followed by a line containing -1. Each test case is a line containing an integer 0 <= n <= 30.

Output

For each test case, output one integer number giving the number of possible tilings.

Sample Input

2

8

12

-1

Sample Output

3

153

2131

Source

Waterloo local 2005.09.24