import sys
sys.setrecursionlimit(10*6)

n, m = map(int, input().split())
A = [int(input()) for _ in range(m)]
cnt = 0


def forward(steps):
    global cnt
    if steps > n:
        return
    if steps == n:
        cnt += 1
        return
    elif steps in A:
        return

    forward(steps + 1)
    forward(steps + 2)


forward(0)
print(cnt % 1000000007)
