#D1924. Tak and Cards
Tak and Cards
Tak and Cards
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
inputFormat
Input
The input is given from Standard Input in the following format:
N A x_1 x_2 ... x_N
outputFormat
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
样例
4 8
7 9 8 9
5