INF = 1 << 60

m = int(input())
n = int(input())
c = list(map(int, input().split()))

dp = [- INF for _ in range(m + 1)]
dp[m] = 0
for cur in range(m, 0, -1):
  if dp[m] == - INF:
    continue
  for i in range(n):
    nxt = cur - c[i]
    if nxt >= 0:
      dp[nxt] = max(dp[nxt], dp[cur] + 1)

div = [None for _ in range(m + 1)]
div[0] = 1
div[1] = 1
for x in range(m + 1):
  if not div[x] is None:
    continue
  for y in range(x, m + 1, x):
    if div[y] is None:
      div[y] = x

ans = max(dp)
for x in range(2, m + 1):
  if dp[x] > 0 and div[x] == x:
    ans += dp[x]

print(ans)