Tri Tiling

Time Limit: 2000/1000 MS (Java/Others)

Memory Limit: 65536/32768 K (Java/Others)

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

Hint

Eddy

Source

University of Waterloo Local Contest 2005.0

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