output_description: Print the largest integer that can be formed with exactly N matchsticks under
  the conditions in the problem statement.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N M
      A_1 A_2 ... A_M
attempt: n, m = map(int, input().split(" "))
  useable_numbers = list(sorted(map(int, input().split(" "))))
  required_maches = {1: 2, 2: 5, 3: 5, 4: 4, 5: 5, 6: 6, 7: 3, 8: 7, 9: 6}
  
  dp = dict()
  
  
  def evaluate(used_numbers):
      if used_numbers == []:
          return 0
      return int("".join(map(str, sorted(used_numbers, reverse=True))))
  
  
  def find(used_matches):
      if used_matches in dp:
          return dp[used_matches]
      if used_matches == 0:
          dp[used_matches] = []
          return dp[used_matches]
      if used_matches < 0:
          dp[used_matches] = None
          return dp[used_matches]
  
      candidates = [
          ai
          for ai in useable_numbers
          if find(used_matches - required_maches[ai]) is not None
      ]
      if candidates == []:
          dp[used_matches] = None
          return dp[used_matches]
  
      max_ai = max(
          candidates,
          key=lambda ai: evaluate(find(used_matches - required_maches[ai]) + [ai]),
      )
      dp[used_matches] = find(used_matches - required_maches[max_ai]) + [max_ai]
      return dp[used_matches]
  
  
  print(evaluate(find(n)))
  
problem_description: Statement
  
  Find the largest integer that can be formed with exactly N matchsticks, under
  the following conditions:
  
    * Every digit in the integer must be one of the digits A_1, A_2, ..., A_M (1 \leq A_i \leq 9).
    * The number of matchsticks used to form digits 1, 2, 3, 4, 5, 6, 7, 8, 9 should be 2, 5, 5, 4, 5, 6, 3, 7, 6, respectively.
samples: [{"input": "20 4\n    3 7 8 4", "output": "777773\n    \n\nThe integer 777773 can be formed with 3 + 3 + 3 + 3 + 3 + 5 = 20 matchsticks,\nand this is the largest integer that can be formed by 20 matchsticks under the\nconditions.\n\n* * *"}, {"input": "101 9\n    9 8 7 6 5 4 3 2 1", "output": "71111111111111111111111111111111111111111111111111\n    \n\nThe output may not fit into a 64-bit integer type.\n\n* * *"}, {"input": "15 3\n    5 4 6", "output": "654"}]