题目描述
There are n+2 people sitting in a line, numbered from 0 to n+1. Some K distinct people with numbers ranging between 1 and n (inclusive) have letters given to them. The role of people with letters is to give their letters to one person sitting adjacent to them. At the end of this procedure, let X denote the sum of the numbers of all the people who have letters. Find the number of possible ways that X can equal a given number, T, modulo 10^9 + 7.
Note, if a person has two letters, count him/her twice.
Input:
The first line contains three integers, N, K, and T, in that order.
Next line consists of K integers, the numbers of the people who have letters.
Output:
Output the answer to the problem.
Constraints:
1 ≤ N ≤ 2000
1 ≤ K ≤ 2000
1 ≤ T ≤ 4000000
1 ≤ Number of everyone who has a letter ≤ N
SAMPLE INPUT
3 1 1
2
SAMPLE OUTPUT
1
Explanation
In order for this to work, person 2 must pass the letter to person 1. So, there is exactly 1 way.
输入格式
见题面
输出格式
见题面