题目描述
Tak has N cards. On the $i-th (1 \leq i \leq N)$ card is written an integer x_i. He is selecting one or more cards from these N cards, so that the average of the integers written on the selected cards is exactly A. In how many ways can he make his selection?
Constraints
- $1 \leq N \leq 50$
- $1 \leq A \leq 50$
- $1 \leq x_i \leq 50$
- N,\,A,\,x_i are integers.
Input
The input is given from Standard Input in the following format:
N A
x_1 x_2 ... x_N
Output
Print the number of ways to select cards such that the average of the written integers is exactly A.
Examples
Input
4 8
7 9 8 9
Output
5
Input
3 8
6 6 9
Output
0
Input
8 5
3 6 2 8 7 6 5 9
Output
19
Input
33 3
3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
Output
8589934591
输入格式
见题面
输出格式
见题面
样例输入
4 8
7 9 8 9
样例输出
5