#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define drep(i,j,n) for(int i=0;i<(int)(n-1);i++)for(int j=i+1;j<(int)(n);j++)
#define trep(i,j,k,n) for(int i=0;i<(int)(n-2);i++)for(int j=i+1;j<(int)(n-1);j++)for(int k=j+1;k<(int)(n);k++)
#define codefor int test;scanf("%d",&test);while(test--)
#define INT(...) int __VA_ARGS__;in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__;in(__VA_ARGS__)
#define yes(ans) if(ans)printf("yes\n");else printf("no\n")
#define Yes(ans) if(ans)printf("Yes\n");else printf("No\n")
#define YES(ans) if(ans)printf("YES\n");else printf("NO\n")
#define popcount(v) __builtin_popcount(v)
#define vector2d(type,name,h,...) vector<vector<type>>name(h,vector<type>(__VA_ARGS__))
#define vector3d(type,name,h,w,...) vector<vector<vector<type>>>name(h,vector<vector<type>>(w,vector<type>(__VA_ARGS__)))
using namespace std;
using ll = long long;
template<class T> using rpriority_queue = priority_queue<T, vector<T>, greater<T>>;
const int MOD=1000000007;
const int MOD2=998244353;
const int INF=1<<30;
const ll INF2=1LL<<60;
//入力系
void scan(int& a){scanf("%d",&a);}
void scan(long long& a){scanf("%lld",&a);}
template<class T,class L>void scan(pair<T, L>& p){scan(p.first);scan(p.second);}
template<class T,class U,class V>void scan(tuple<T,U,V>& p){scan(get<0>(p));scan(get<1>(p));scan(get<2>(p));}
template<class T> void scan(T& a){cin>>a;}
template<class T> void scan(vector<T>& vec){for(auto&& it:vec)scan(it);}
void in(){}
template <class Head, class... Tail> void in(Head& head, Tail&... tail){scan(head);in(tail...);}
//出力系
void print(const int& a){printf("%d",a);}
void print(const long long& a){printf("%lld",a);}
void print(const double& a){printf("%.15lf",a);}
template<class T,class L>void print(const pair<T, L>& p){print(p.first);putchar(' ');print(p.second);}
template<class T> void print(const T& a){cout<<a;}
template<class T> void print(const vector<T>& vec){if(vec.empty())return;print(vec[0]);for(auto it=vec.begin();++it!= vec.end();){putchar(' ');print(*it);}}
void out(){putchar('\n');}
template<class T> void out(const T& t){print(t);putchar('\n');}
template <class Head, class... Tail> void out(const Head& head,const Tail&... tail){print(head);putchar(' ');out(tail...);}
//デバッグ系
template<class T> void dprint(const T& a){cerr<<a;}
template<class T> void dprint(const vector<T>& vec){if(vec.empty())return;cerr<<vec[0];for(auto it=vec.begin();++it!= vec.end();){cerr<<" "<<*it;}}
void debug(){cerr<<endl;}
template<class T> void debug(const T& t){dprint(t);cerr<<endl;}
template <class Head, class... Tail> void debug(const Head& head, const Tail&... tail){dprint(head);cerr<<" ";debug(tail...);}
ll intpow(ll a, ll b){ ll ans = 1; while(b){ if(b & 1) ans *= a; a *= a; b /= 2; } return ans; }
ll modpow(ll a, ll b, ll p){ ll ans = 1; while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }
ll modinv(ll a, ll m) {ll b = m, u = 1, v = 0;while (b) {ll t = a / b;a -= t * b; swap(a, b);u -= t * v; swap(u, v);}u %= m;if (u < 0) u += m;return u;}
ll updivide(ll a,ll b){return (a+b-1)/b;}
template<class T> void chmax(T &a,const T b){if(b>a)a=b;}
template<class T> void chmin(T &a,const T b){if(b<a)a=b;}

template <class T>vector<T> compress(vector<T> &x) {
	auto res = x;
	sort(res.begin(), res.end());
	res.erase(unique(res.begin(),res.end()),res.end());
	for(int i = 0; i < (int)x.size(); i++)
		x[i] = lower_bound(res.begin(), res.end(), x[i]) - res.begin();
	return res;
}

//2次元累積和
template< class T > struct CumulativeSum2D{
    vector<vector<T>> data;
    CumulativeSum2D(int H, int W) : data(H + 1, vector<T>(W + 1, 0)) {}
    void add(int y, int x, int z){
        y++, x++;
        if(y>=data.size()||x>=data[0].size())return;
        data[y][x]+=z;
    }
    void build(){
        for(int i=1;i<data.size();i++) {
            for(int j=1;j<data[i].size();j++) {
                data[i][j]+=data[i][j-1]+data[i-1][j]-data[i-1][j-1];
            }
        }
    }
    T query(int sy,int sx,int gy, int gx){
        return (data[gy][gx]-data[sy][gx]-data[gy][sx]+data[sy][sx]);
    }
};

int main(){
    INT(n,b);
    vector<int> x(n),y(n),p(n),xc,yc;
    rep(i,n){
        in(x[i],y[i],p[i]);
    }
    xc=compress(x);
    yc=compress(y);
    CumulativeSum2D<int> A(405,405),B(405,405);
    rep(i,n){
        A.add(x[i],y[i],p[i]);
        B.add(x[i],y[i],1);
    }
    sort(all(x));
    sort(all(y));
    x.push_back(402);
    y.push_back(402);
    A.build();
    B.build();
    int ans=0,xs,ys,xt,yt;
    drep(i,j,n+1){
        for(int l=0,r=0;l<n;l++){
            while(A.query(x[i],y[l],x[j],y[r])<=b){
                chmax(ans,B.query(x[i],y[l],x[j],y[r]));
                if(r<n)r++;
                else break;
            }
        }
    }
    out(ans);
}