Problem:
Score : 400 points

Problem 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.

Constraints

All values in input are integers.

2 \leq N \leq 10^4

1 \leq M \leq 9

1 \leq A_i \leq 9

A_i are all different.

There exists an integer that can be formed by exactly N matchsticks under the conditions.

Input

Input is given from Standard Input in the following format:

N M
A_1 A_2 ... A_M

Output

Print the largest integer that can be formed with exactly N matchsticks under the conditions in the problem statement.

Sample Input 1

20 4
3 7 8 4

Sample Output 1

777773

The integer 777773 can be formed with 3 + 3 + 3 + 3 + 3 + 5 = 20 matchsticks, and this is the largest integer that can be formed by 20 matchsticks under the conditions.

Sample Input 2

101 9
9 8 7 6 5 4 3 2 1

Sample Output 2

71111111111111111111111111111111111111111111111111

The output may not fit into a 64-bit integer type.

Sample Input 3

15 3
5 4 6

Sample Output 3

654

Solution in Python (3.4.3) (judge verdict: Runtime Error)

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import itertools


def main():
  r = (99, 2, 5, 5, 4, 5, 6, 3, 7, 6)
  n, _ = list(map(int, input().split()))
  ps = list(map(int, input().split()))

  cs = [(p, r[p]) for p in ps]
  cs.sort(key=lambda x: x[1])
  a = []
  s, b = cs[0]

  while n - b > 0:
    a.append(s)
    n -= b

  cs.sort(key=lambda x:-x[0])
  cs = [(p, c - b) for p, c in cs if c != b]
  ds = None

  for i in range(1, len(cs) + 1):
    for ps in itertools.product(range(len(cs)), repeat=i):
      if sum(cs[p][1] for p in ps) == n:
        ds = [cs[p][0] for p in ps]
        break

    if ds is not None:
      break

  uds = [d for d in ds if d >= s]
  lds = [d for d in ds if d < s][::-1]

  a = uds + a[len(uds):]
  a = a[-len(lds):] + lds

  print(''.join(str(v) for v in a), flush=True)


if __name__ == '__main__':
  main()