You are given an even number of people numPeople that stand around a circle and each person shakes hands with someone else so that there are numPeople / 2 handshakes total.

Return the number of ways these handshakes could occur such that none of the handshakes cross.

Since the answer could be very large, return it modulo 109 + 7.

 

Example 1:

Input: numPeople = 4
Output: 2
Explanation: There are two ways to do it, the first way is [(1,2),(3,4)] and the second one is [(2,3),(4,1)].

Example 2:

Input: numPeople = 6
Output: 5

 

Constraints:

• 2 <= numPeople <= 1000
• numPeople is even.