import std.algorithm, std.array, std.container, std.range, std.bitmanip;
import std.numeric, std.math, std.bigint, std.random, core.bitop;
import std.string, std.regex, std.conv, std.stdio, std.typecons;

class BiTree(T) {
  T[] b; // buffer
  size_t s; // size

  this(size_t t) {
    s = t;
    b = new int[](s + 1);
  }

  int get(size_t i) {
    if (!i) return 0;
    return b[i] + get(i - (i & -i));
  }

  void add(size_t i, T v) {
    if (i > s) return;
    b[i] += v;
    add(i + (i & -i), v);
  }
}

void main()
{
  auto rd = readln.split;
  auto n = rd[0].to!size_t, b = rd[1].to!int;
  auto pi = iota(n).map!(_ => readln.split.map!(to!int)).array;

  auto xi = pi.map!("a[0]").array;
  auto hx = compressMap(xi);
  auto w = hx.length;

  auto yi = pi.map!("a[1]").array;
  auto hy = compressMap(yi);
  auto h = hy.length;

  auto bitCi = new BiTree!int[](h);
  auto bitQi = new BiTree!int[](h);
  foreach (i; 0..h) {
    bitCi[i] = new BiTree!int(w);
    bitQi[i] = new BiTree!int(w);
  }

  foreach (p; pi) {
    bitCi[hy[p[1]]].add(hx[p[0]] + 1, 1);
    bitQi[hy[p[1]]].add(hx[p[0]] + 1, p[2]);
  }

  auto maxC = 0;
  foreach (i; 0..w-1)
    foreach (j; i..w) {
      auto ci = iota(h).map!(k => bitCi[k].get(j + 1) - bitCi[k].get(i));
      auto qi = iota(h).map!(k => bitQi[k].get(j + 1) - bitQi[k].get(i));

      auto k = 0, l = 0, sumC = 0, sumQ = 0;
      while (true) {
        ++l;
        if (l > h) break;
        sumC += ci[l - 1];
        sumQ += qi[l - 1];
        if (sumQ <= b)
          maxC = max(maxC, sumC);

        while (sumQ > b) {
          ++k;
          sumC -= ci[k - 1];
          sumQ -= qi[k - 1];
        }
      }
    }

  writeln(maxC);
}

int[int] compressMap(int[] pi)
{
  pi = pi.sort().array.uniq().array;
  int[int] h;
  foreach (i, p; pi) h[p] = i.to!int;
  return h;
}