n, m = map(int, input().split())
a = []
for _ in range(m):
    _a = int(input())
    try:
        if _a == a[-1]:
            continue
    except:
        pass
    a.append(_a)
a.append(n + 1)
m = len(a)

memo = {0: 1, 1: 1, 2: 2}
def chk(n):
    if n in memo:
        return memo[n]
    else:
        make(n)
        return memo[n]

def make(n):
    if n in memo:
        return
    make(n - 1)
    make(n - 2)
    memo[n] = memo[n-1] + memo[n-2]

for i in range(m - 1):
    if a[i] + 1 == a[i + 1]:
        print(0)
        exit()

cur = 0
tot = 1
#from sys import stderr
#for k in range(100):
#    print(f'0-{k}: {chk(k)}', file=stderr)

for i in range(m):
    nxt = a[i] - 1
    add = chk(nxt - cur)
    #print(f'{cur}-{nxt}: {add}', file=stderr)
    tot *= add
    tot %= 1000000007
    cur = nxt + 2
print(tot % 1000000007)
