参考博客：http://www.cnblogs.com/chendl111/p/6891770.html
题目链接：https://www.icpc.camp/contests/4mYguiUR8k0GKE
Parentheses
Input
The input contains zero or more test cases and is terminated by end-of-file. For each test case: The first line contains an integer n. The i-th of the following n lines contains li , ci , di .
• 1 ≤ n ≤ 105 • 1 ≤ l1 + l2 + · · · + ln ≤ 109
• l1 + l2 + · · · + ln is even.
• 1 ≤ di ≤ 109
• The sum of n does not exceed 106 .