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: from itertools import permutations
  
  n, m = list(map(int, input().split()))
  aa = list(map(int, input().split()))
  
  match = [6, 2, 5, 5, 4, 5, 6, 3, 7, 6]
  
  minm = min(match[a] for a in aa)
  keta = n // minm
  
  if m == 1:
      print(str(aa[0]) * keta)
  elif m == 2:
      ans_best = 0
      for a0, a1 in permutations(aa, 2):
          m0, m1 = match[a0], match[a1]
          for i in range(min(6, keta)):
              ans = int(str(a0) * i + str(a1) * (keta - i))
              if m0 * i + m1 * (keta - i) == n:
                  ans_best = max(ans_best, ans)
              ans = int(str(a0) * (keta - i) + str(a1) * i)
              if m0 * (keta - i) + m1 * i == n:
                  ans_best = max(ans_best, ans)
      print(ans_best)
  else:
      ans_best = 0
      for a0, a1, a2 in permutations(aa, 3):
          m0, m1, m2 = match[a0], match[a1], match[a2]
          for i in range(min(6, keta)):
              for j in range(min(6, keta) - i):
                  ans = int(str(a0) * i + str(a1) * j + str(a2) * (keta - i - j))
                  if m0 * i + m1 * j + m2 * (keta - i - j) == n:
                      ans_best = max(ans_best, ans)
                  ans = int(str(a0) * i + str(a1) * (keta - i - j) + str(a2) * j)
                  if m0 * i + m1 * (keta - i - j) + m2 * j == n:
                      ans_best = max(ans_best, ans)
                  ans = int(str(a0) * (keta - i - j) + str(a1) * i + str(a2) * j)
                  if m0 * (keta - i - j) + m1 * i + m2 * j == n:
                      ans_best = max(ans_best, ans)
      print(ans_best)
  
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"}]