import sys,math
N,M = map(int,input().split())
a = []
cnt = 0
ans = 1
fi = []
fi.append(1)
fi.append(1)
fi.append(1)
for i in range(3,10*5+2):
    tmp = fi[i-1]+fi[i-2]
    fi.append(tmp)
for i in range(M):
    a.append(int(input()))
for i in range(N+1):
    if i in a:
        if cnt == 0:
            print(0)
            sys.exit()
        else:
            ans *= fi[cnt]
            cnt = 0
    else:
        cnt += 1
ans *= fi[cnt]

print(ans % 1000000007)