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 = list(map(int, input().split()))
  d = {1: 2, 2: 5, 3: 5, 4: 4, 5: 5, 6: 6, 7: 3, 8: 7, 9: 6}
  D = {a: d[a] for a in A}
  m = min(D.values())
  E = {}
  for k, v in D.items():
      v -= m
      if v in E:
          E[v] = max(E[v], k)
      else:
          E[v] = k
  F = sorted(E.keys(), key=lambda f: (max(0, E[f] - E[0]), f), reverse=True)
  F.remove(0)
  K = N // m
  for k in range(K, 0, -1):
      B = [E[0]] * k
      R = N - k * m
      if not R:
          print("".join(map(str, sorted(B, reverse=True))))
          break
  
      def rec(r, i, j):
          if i < 0:
              return
          for f in F[j:]:
              if r == f:
                  B[i] = E[f]
                  print("".join(map(str, sorted(B, reverse=True))))
                  exit()
              elif r > f:
                  B[i], tmp = E[f], B[i]
                  rec(r - f, i - 1, j)
                  B[i] = tmp
              j += 1
  
      rec(R, k - 1, 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"}]