import sys
input = sys.stdin.readline

n, m = map(int, input().split())
broken_steps = [int(input()) for _ in range(m)]
#print(broken_steps)

def ptn_num(x): # 'x'stepまでのパターン数
    if x == 1:
        return 1
    else:
        dp = [0] * (x+1) # DP枠_including step'0'
        cnt = 0
        if broken_steps[0] == 1: # in case, step'1' broken 
            dp[:2] = 1, 0
        else:
            dp[:2] = 1, 1 # Usually

        for i in range(2, x+1):
            if i in broken_steps: # 階段が壊れている場合...
                cnt += 1
                if cnt == 2:
                    print(0)
                    exit()
            else: # 階段が壊れてない場合...
                dp[i] = (dp[i-1] + dp[i-2]) % (10**9+7)
                cnt = 0
        
        print(dp[n])

ptn_num(n)
