import sys
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9 + 7
input = sys.stdin.readline

def inp():
    return int(input())
def inpl():
    return list(map(int,input().split()))
def inpm():
    return map(int,input().split())

n,m = inpm()
dp = [0] * (n+2)
for _ in range(m):
    a = int(input())
    dp[a] = -1

# init
dp[0] = 1
# start
print(a)
for i in range(n):
    if dp[i] == -1:continue
    dp[i] %= mod
    if dp[i+1] != -1:
        dp[i+1] += dp[i]
    if dp[i+2] != -1:
        dp[i+2] += dp[i]

print(dp[n]%mod)
