def countStep(n):
    global S, b
    if n==-1:
        return 0
    elif n==0:
        return 1
    elif str(n) in b:
        count = S[n]
        return count
    else:
        count1 = countStep(n-1)
        count2 = countStep(n-2)
        count = count1 + count2
        b.append(str(n))
        S[n] = count
        return count

N,M = map(int,input().split())
b = []
for _ in range(M):
  b.append(input())
S = [0] * (N+1)

print(countStep(N) % 1000000007)

