output_description: Print the number of ways to select cards such that the average of the written
  integers is exactly A.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      N A
      x_1 x_2 ... x_N
attempt: from subprocess import *
  
  call(
      (
          "pypy3",
          "-c",
          """
  n,a,*x=map(int,open(0).read().split())
  x=[0]+x
  dp=[[[0]*(50*n+1)for j in range(n+1)]for i in range(n+1)]
  dp[0][0][0]=1
  for i in range(1,n+1):
    dp[i][0]=dp[i-1][0]
    for j in range(1,n+1):
      for k in range(1,50*n+1):
        dp[i][j][k]=dp[i-1][j][k]
        if k-x[i]>=0:
          dp[i][j][k]+=dp[i-1][j-1][k-x[i]]
  ans=0
  for i in range(1,n+1):
    j=i*a
    if j<50*n+2:
      ans+=dp[-1][i][j]
  print(ans)
  """,
      )
  )
  
problem_description: Statement
  
  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?
samples: [{"input": "4 8\n    7 9 8 9", "output": "5\n    \n\n  * The following are the 5 ways to select cards such that the average is 8:\n    * Select the 3-rd card.\n    * Select the 1-st and 2-nd cards.\n    * Select the 1-st and 4-th cards.\n    * Select the 1-st, 2-nd and 3-rd cards.\n    * Select the 1-st, 3-rd and 4-th cards.\n\n* * *"}, {"input": "3 8\n    6 6 9", "output": "0\n    \n\n* * *"}, {"input": "8 5\n    3 6 2 8 7 6 5 9", "output": "19\n    \n\n* * *"}, {"input": "33 3\n    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\n    \n\n  * The answer may not fit into a 32-bit integer."}]