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: num,ave = map(int,input().split())
  numx = list(map(int,input().split()))
  
  L = len(numx)
  numy = [0] * L
  for i in range(L):
      numy[i] = numx[i] - ave
  
  if abs(min(numy)) < abs(max(numy)):
      maxX = max(numy)
  else:
      maxX = abs(min(numy))
  
  dp = [[0]*(2*maxX*L+1) for _ in range(L+1)]
  dp[0][maxX*L] = 1
  for i in range(L):
      for j in range(2*maxX*L+1):
          if (j-numy[i]) < 0 or (j - numy[i]) > 2*maxX*L:
              dp[i+1][j] = dp[i][j]
          else
          dp[i+1][j] = dp[i][j] + dp[i][j-numy[i]]
  print(dp[L][maxX*L]-1)
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."}]