def step(n, memo={}):
    if n <= 1:
        return 1
    elif n == 2:
        return 2
    elif n in memo:
        return memo[n]
    else:
        memo[n] = (step(n-1,memo)+step(n-2,memo))%1000000007
        return memo[n]

N, M = map(int, input().split())
a = [-1]

for m in range(M):
    a.append(int(input()))
    if a[m+1] - a[m] == 1:
        print(0)
        break
else:
    a.append(N+1)
    ans = 1
    for m in range(M+1):
        ans = (ans*(step(a[m+1]-a[m]-2)))%1000000007
    print(ans)