N, M = map(int, input().split())
D=[1]*(N+1)
MOD=1000000007
for _ in range(M):
    i = int(input())
    D[i]=0

C = [0]*(N+1)
C[0]=1
for i in range(N-1):
    C[i+1]+=(C[i]*D[i])%MOD
    C[i+2]+=(C[i]*D[i])%MOD
C[N]+=(C[N-1]*D[N-1])%MOD
    #print(C)
print(C[N])
