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())
  num = list(map(int, input().split()))
  num_dic = {1: 2, 2: 5, 3: 5, 4: 4, 5: 5, 6: 6, 7: 3, 8: 7, 9: 6}
  
  dp = [0] * (n + 1)
  
  
  def creat_num(original, num):  # original=431,num=1 return 4311
      if original == 0:
          return num
      new = list(map(int, list(str(original)))) + [num]
      new.sort()
      new.reverse()
      return int("".join(list(map(str, new))))
  
  
  def match_dp(dp, num, num_dic, n):
      for i in num:
          if n - num_dic[i] >= 0:
              new_num = creat_num(dp[n], i)
              dp[n - num_dic[i]] = max(new_num, dp[n - num_dic[i]])
              match_dp(dp, num, num_dic, n - num_dic[i])
  
  
  match_dp(dp, num, num_dic, n)
  
  print(dp[0])
  
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"}]