import numpy as np
from scipy.signal import fftconvolve


def convolve(A, B):
    n = len(A) + len(B) + 1
    fft_len = 1 << (n - 1).bit_length()
    fa = np.fft.rfft(A, fft_len)
    fb = np.fft.rfft(B, fft_len)
    res = np.fft.irfft(fa * fb, fft_len)[:n + 1]
    return np.rint(res + 0.01).astype(np.int32)


N, X = map(int, input().split())
A = np.array(input().split(), dtype=np.int32)
A = np.bincount(A)

F = convolve(A, A)
if X < len(F):
    print(F[X])
else:
    print(0)