n,b = map(int,input().split())
xyp = []
sx = set()
sy = set()
for _ in range(n):
    x,y,p = map(int,input().split())
    xyp.append((x,y,p))
    sx.add(x)
    sy.add(y)
*sx, = sorted(sx)
*sy, = sorted(sy)
zx = {si:i for i,si in enumerate(sx)}
zy = {si:i for i,si in enumerate(sy)}

lx = len(sx)
ly = len(sy)
cnt = [[0]*ly for _ in range(lx)]
pts = [[0]*ly for _ in range(lx)]
for x,y,p in xyp:
    cnt[zx[x]][zy[y]] += 1
    pts[zx[x]][zy[y]] += p

for i in range(lx):
    for j in range(1,ly):
        cnt[i][j] += cnt[i][j-1]
        pts[i][j] += pts[i][j-1]
for j in range(ly):
    for i in range(1,lx):
        cnt[i][j] += cnt[i-1][j]
        pts[i][j] += pts[i-1][j]

def get_sum(a,h1,h2,w1,w2): #閉長方形 [h1からh2]*[w1からw2] の和
    if h1 and w1: return a[h2][w2] - a[h1-1][w2] - a[h2][w1-1] + a[h1-1][w1-1]
    elif h1: return a[h2][w2] - a[h1-1][w2]
    elif w1: return a[h2][w2] - a[h2][w1-1]
    else: return a[h2][w2]

ans = 0
for x0 in range(lx):
    for y0 in range(ly):
        y1 = ly-1
        for x1 in range(x0,lx):
            while y0 <= y1 and get_sum(pts,x0,x1,y0,y1) > b:
                y1 -= 1
            if y0 > y1: break
            ans = max(ans,get_sum(cnt,x0,x1,y0,y1))
print(ans)