from collections import deque

N, M = map(int, input().split())
A = [int(input()) for _ in range(M)]

tmp = deque([0])

res = 0
while True:
    if tmp:
        now = tmp.popleft()
        
        if now + 1 <= N:
            
            if now + 1 == N:
                res += 1
                
            elif now + 1 in A:
                pass
            
            else:
                tmp.append(now + 1)
                
            
        if now + 2 <= N:
            
            if now + 2 == N:
                res += 1
                
            elif now + 2 in A:
                pass
            
            else:
                tmp.append(now + 2)
            
    else:
        break
            
print(res%(10 ** 9 + 7))
            
        