N, M = map(int, input().split())

A    = [int(input()) for _ in range(M)]

dp = [0]*(N+3)



for i in range(N+1):

    if i==0:
        if not (i+1) in A:
            dp[i+1] = 1 + dp[i]
        if not (i+2) in A:
            dp[i+2] = 1 + dp[i]
        continue 
    if not i+1 in A:
        dp[i+1] = dp[i] + dp[i+1]
    if not i+2 in A:
        dp[i+2] = dp[i] + dp[i+2]

print(dp[N]%(1000000007))