n, m = map(int, input().split())
broken = []
for i in range(m):
    broken.append(int(input()))
    
num = [0] * (n + 1)
num[0] = int(0 not in broken)
num[1] = int(1 not in broken)

for i in range(2, n):
    if i in broken:
        num[i] = 0
    else:
        num[i] = (num[i-1] + num[i-2])%1000000007
        
if n <= 1:
    print(num[n])
else:
    print((num[n-1]+num[n-2])%1000000007)