Brackets
Brackets
题目描述
This year MK is 5 years old. So he decides to learn some arithmetic. But he was confused by how to write the brackets. He has already known that the brackets should match when writing them correctly. Such as “()(())” is correct but “())(” is not.
The problem is that, if there are N pairs of brackets, how many ways that MK can write them correctly?
输入说明
There are several test cases. Each case contains a number N (1 <= N <= 1000) indicating the pairs of brackets.
输出说明
For each case, please output the answer mod 1,000,000,007.
样例
输入
5
7
输出
42
429