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())
  a = sorted(list(map(int, input().split())))
  match = [0, 2, 5, 5, 4, 5, 6, 3, 7, 6]
  move = [0, 0, 0, 0, 0, 0]
  for i in a:
      stick = match[i]
      move[stick - 2] = i
  dp = [[0, 0, 0, 0, 0, 0] for i in range(n + 10)]
  for i in range(n):
      if not any(dp[i]):
          if i:
              continue
      for k, v in enumerate(move, 2):
          if v:
              dp[i + k] = list()
              for k2, v2 in enumerate(dp[i]):
                  if k - 2 == k2:
                      v2 += 1
                  dp[i + k].append(v2)
  ANS = sorted([[i, j] for i, j in zip(move, dp[n])], reverse=True)
  ans = ""
  for i, j in ANS:
      ans += str(i) * j
  print(ans)
  
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"}]