text: import sys
  input = sys.stdin.readline
  sys.setrecursionlimit(10**6)
  
  n, m = map(int, input().split())
  a = []
  for _ in range(m):
      a.append(int(input()))
  a=set(a)
  
  memo = [0]*(n+1)
  memo[0]=1
  if not(1 in a):
      memo[1]=1
  
  for i in range(2,n+1):
      #print(i)
      if i in a:
          continue
      #print(memo[i-1],memo[i-2])
      memo[i]=memo[i-2]+memo[i-1]
              
  
  #print(memo)
  print(memo[n]% 1000000007)
  