import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import numpy as np

N,K = map(int,readline().split())
A = np.array(read().split(),np.int64)

A.sort()

cand = np.searchsorted(A,(K-A),'right') # 自分のペアにできる人数

mid = np.searchsorted(A,K//2,'right')

x = (cand - np.arange(N)[::-1])[mid:]

rest = N - 2 * len(x)
x = np.concatenate([x,np.arange(1,rest,2)])

MOD = 10 ** 9 + 7

def cumprod(A, MOD = MOD):
    L = len(A); Lsq = int(L**.5+1)
    A = np.resize(A, Lsq**2).reshape(Lsq,Lsq)
    for n in range(1,Lsq):
        A[:,n] *= A[:,n-1]; A[:,n] %= MOD
    for n in range(1,Lsq):
        A[n] *= A[n-1,-1]; A[n] %= MOD
    return A.ravel()[:L]

answer = cumprod(x)[-1]
print(answer)