N,K=map(int,input().split())
A=list(map(int,input().split()))
A.sort()
ans=1
mod=10**9+7
b=0
for i in range(N-1,-1,-1):
    while b<N and A[i]+A[b]<=K:
        b+=1
    if i<=b:
        cnt=N-2*(N-1-i)
        if cnt<0:
            ans=0
        else:
            for c in range(1,cnt,2):
                ans*=c
                ans%=mod
        break
    else:
        ans*=b-(N-1-i)
        ans%=mod
print(ans)