#import sys
#sys.setrecursionlimit(10 ** 7)
'''
#import numpy as np
import math, string, itertools, fractions, heapq, collections, re, array, bisect, copy, functools, random
from collections import deque, defaultdict, Counter
from heapq import heappush, heappop
from itertools import permutations, combinations, product, accumulate, groupby
from bisect import bisect_left, bisect_right, insort_left, insort_right
from operator import itemgetter as ig
#sys.setrecursionlimit(10 ** 7)
'''
#inf = 10 ** 20
'''
INF = float("INF")
mod = 10 ** 9 + 7
"""dd = [(-1, 0), (0, 1), (1, 0), (0, -1)];
ddn = dd + [(-1, 1), (1, 1), (1, -1), (-1, -1)];
ddn9 = ddn + [(0, 0)]
for dx, dy in dd:
        nx = j + dx; ny = i + dy
            if 0 <= nx < w and 0 <= ny < h:"""

def wi(): return list(map(int, sys.stdin.readline().split()))
def wip(): return [int(x) - 1 for x in sys.stdin.readline().split()]  # WideIntPoint
def ws(): return sys.stdin.readline().split()
def si(): return int(sys.stdin.readline())  # SingleInt
def ss(): return input()
def hi(n): return [si() for _ in range(n)]
def hs(n): return [ss() for _ in range(n)]  # HeightString
def s_list(): return list(input())
def mi(n): return [wi() for _ in range(n)]  # MatrixInt
def mip(n): return [wip() for _ in range(n)]
def ms(n): return [ws() for _ in range(n)]
def num_grid(n): return [[int(i) for i in sys.stdin.readline().split()[0]] for _ in range(n)]  # NumberGrid
def grid(n): return [s_list() for _ in range(n)]

'''
def binary_search(num_list, target):
    # 「値が何番目にあるか」を確認するための変数
    ans_counter = 0
    while True:
        # 配列の中心にある値を取り出す
        middle = num_list[len(num_list) // 2]
        # 配列の左側
        left = num_list[:len(num_list) // 2]
        # 配列の右側
        right = num_list[len(num_list) // 2:]
        # 中心の値が探索値と一致したら探索終了(探索値発見)
        if middle == target:
            ans_counter += len(left) + 1
            #print("{}は{}番目にありました。".format(target, ans_counter))
            return True
            break
        # 値が最後の1個になっても一致しなかったら探索終了(探索値不存在1)
        # 左の最大値 < 探索値 < 右の最小値となった場合探索終了(探索値不存在2)
        elif len(num_list) == 1 and num_list[0] != target\
                or left[-1] < target < right[0]:
            #print("{}はありませんでした。".format(target))
            return False
            break
        # 左の最大値より探索値が小さい場合、探索範囲を左側に絞る
        elif target <= left[-1]:
            num_list = left
        # 右の最小値より探索値が大きい場合、探索範囲を右側に絞る
        elif right[0] < target:
            ans_counter += len(left)
            num_list = right

def main():
    N, M = map(int, input().split())
    a = [int(input()) for _ in range(M)]
    dp = [1] * N
    if 1 in a:
        dp[0] = 0
        for i in range(1,N):
            if binary_search(a, i+1):
                dp[i] = 0
            else:
                dp[i] = dp[i-1] + dp[i-2]
        print(dp[N-1] % (10**9+7))
    else:
        for i in range(1,N):
            if binary_search(a, i + 1):
                dp[i] = 0
            else:
                dp[i] = dp[i-1] + dp[i-2]
        print(dp[N-1] % (10**9+7))

if __name__ == '__main__':
    main()


### FIXED CODE ###

def main():
    N, M = map(int, input().split())
    a = [int(input()) for _ in range(M)]
    b = set(a)
    dp = [1] * N
    if 1 in a:
        dp[0] = 0
        for i in range(1, N):
            if i+1 in b:
                dp[i] = 0
            else:
                dp[i] = dp[i-1] + dp[i-2]
        print(dp[N-1] % (10**9+7))
    else:
        for i in range(1, N):
            if i+1 in b:
                dp[i] = 0
            else:
                dp[i] = dp[i-1] + dp[i-2]
        print(dp[N-1] % (10**9+7))


if __name__ == '__main__':
    main()