#include<bits/stdc++.h>
using namespace std;
const int N = 1e3 + 10;
int sum[N][N], n, m, ans; 
int main(){
	cin >> n >> m;
	for(int i = 1; i <= n; i++){
		int x, y, v;
		cin >> x >> y >> v;
		sum[x + 1][y + 1] = v;
	}
    for(int i = 2; i <= 5005; i++){
        for(int j = 2; j <= 5005; j++){
            sum[i][j] += sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1];
		}
	}
	for(int i = m; i <= 5005; i++){
		for(int j = m; j <= 5005; j++){
			int x1 = i - m, y1 = j - m, x2 = i, y2 = j;
			ans = max(ans, sum[x2][y2] - sum[x2][y1] - sum[x1][y2] + sum[x1][y1]);
		}
	}
	cout << ans;
	return 0;
}