import sys

def fibo(n):
    a, b = 0, 1
    if n == 1:
        return 1
    else:
        for i in range(n):
            a0 = a
            a = b
            b = a0 + b
        return b
        
N, M = map(int, input().split())
a = []

if M = 0:
    print(fibo(N))
    sys.exit()

for i in range(M):
    a.append(int(input()))
    
for j in range(len(a)-1):
    if a[j+1] - a[j] == 1:
        print(0)
        sys.exit()
    
hole = 0
pattern = 1

for i, k in enumerate(a):
    if i == 0:
        pattern *= fibo(k-1)
    else:
        if i > 0:
            pattern *= fibo(a[i]-a[i-1]-2)
        
pattern *= fibo(N-a[-1]-1)
print(pattern % 1000000007)