题目描述
In how many ways can you tile a 3xn rectangle with 2x1 dominoes?
Here is a sample tiling of a 3x12 rectangle.
Here is a sample tiling of a 3x12 rectangle.
输入
Input consists of several test cases followed by a line containing -1. Each test case is a line containing an integer 0 <= n <= 30.
输出
For each test case, output one integer number giving the number of possible tilings.
样例输入 Copy
2
8
12
-1
样例输出 Copy
3
153
2131