import sys
input = sys.stdin.readline
sys.setrecursionlimit(10**7)

N, M = map(int, input().split())
a=[]
for _ in range(M):
    a.append(int(input()))

lst=[0]*(N+1)
def func(n):
    if n in a:
        return 0
    if n<=1:
        return 1
    else:
        if lst[n]:
            return lst[n]
        else:
            temp=(func(n-1)+func(n-2))%(10**9+7)
            lst[n]=temp
            return temp

print(func(N))