import sys
import numpy 
import itertools



def get_data():
    N, K = input().split(' ')
    A = input().split(' ')
    A = list(A)
    N = int(N)
    K = int(K)

    return N, K, A


def main():

    N, K, A = get_data()
    

    A_dic = {}
    for i in range(N) :
        A_dic[i] = A[i]
    
    count = 0
    good_list = []

    for (i,j) in list(itertools.combinations(A_dic.keys(), 2)):
        if int(A_dic[i]) + int(A_dic[j]) <= K:
            good_list.append((i,j))
    
    #print(good_list)
    j = ()
    for i in list(itertools.combinations(good_list, int(N / 2))):
        for n in range(int(N / 2)):
            j += i[n]

        j = list(set(j))
        
        if len(j) == N:
            count += 1
        j = ()
    
    print(count)

    
    
    
    


if __name__=="__main__":
    main()