N, M = map(int,input().split())
a = []
dev = 100000007

for _ in range(M):
    aa = int(input())
    a.append(aa)

ans = 0

def dfs(step):
    global ans
    if step == N:
        ans = (ans+1)%dev
        return
    elif step > N:
        return
    
    for ds in (1,2):
        ns = step + ds
        if ns in a:
            continue
        else:
            dfs(ns)

dfs(0)
print(ans)