OnlineJudge 3 现已推出。点此体验新版：Tri Tiling | SDUT OnlineJudge
Time Limit: 1000 ms Memory Limit: 65536 KiB
Problem DescriptionIn how many ways can you tile a 3xn rectangle with 2x1 dominoes? Here is a sample tiling of a 3x12 rectangle.
Input consists of several test cases followed by a line containing -1. Each test case is a line containing an integer 0 ≤ n ≤ 30.
For each test case, output one integer number giving the number of possible tilings.
2 8 12 -1
3 153 2131