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: N, A = map(int, input().split())
  
  x = list(map(int, input().split()))
  
  tmp_max = max(x)
  tmp_max = max(tmp_max, A)
  
  dp = [[[0 for _ in range(tmp_max * N + 1)] for _ in range(N + 1)] for _ i range(N + 1)]
  dp[0][0][0] = 0
  
  for j in range(n + 1):
    for k in range(j + 1):
      for s in range(tmp_max * K + 1):
        if j >= 1 and s < x[j - 1]:
          dp[j][k][s] = dp[j - 1][k][s]
        elif j >= 1 and k >= 1 and s >= x[j - 1]:
          dp[j][k][s] = dp[j - 1][k][s] + dp[j - 1][k - 1][s - x[j - 1]]
          
          
  ans = 0
  for k in range(1, n + 1):
    ans += dp[N][k][k * A]
    
  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."}]