import bisect
n,k = map(int,input().split())
a = [int(i) for i in input().split()]

a.sort()
ans = 1
mod = 10**9+7
cnt = 0

for i in range(n-1,0,-1):
    if i == n//2-1:
        break
    #print(i)
    val = k-a[i]
    idx = bisect.bisect_right(a,val)
    ans *= min(i,idx)-cnt
    ans %= mod
    #print(ans,i,idx-cnt)
    cnt += 1

print(ans)