# ここから
import sys
input = sys.stdin.readline

def resolve():
    n, m = map(int, input().split())
    aa = [int(input()) for _ in range(m)]
    dp = [0] * (n+1)
    dp[0] = 1
    dp[1] = 0 if 1 in aa else 1

    for i in range(2, n+1):
        if i in aa:
            dp[i] = 0
        else:
            dp[i] = (dp[i-2] + dp[i-1]) % 1000000007

    print(dp[n])



resolve()