S=[0]*100010
S[1]=1
S[2]=1
for i in range(3,102):
    S[i]=(S[i-2]+S[i-1])%1000000007

N,M=map(int,input().split())
T=[]
for i in range(M):
    T.append(int(input()))
    if i>=1:
        if T[i]-1==T[i-1]:
            print(0)
            exit()

U=[]
U.append(T[0])
for i in range(1,M):
    U.append(T[i]-T[i-1]-1)

U.append(N-T[M-1])

ans=1
for i in range(len(U)):
    ans=(ans*S[U[i]])%1000000007
print(ans)
