Tri Tiling
Time Limit : 2000/1000ms (Java/Other) Memory Limit : 65536/32768K (Java/Other)
Total Submission(s) : 9 Accepted Submission(s) : 3
Problem 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
University of Waterloo Local Contest 2005.09.24