//It is made by Awson on 2017.10.8

 #include <map>

 #include <set>

 #include <cmath>

 #include <ctime>

 #include <queue>

 #include <stack>

 #include <vector>

 #include <cstdio>

 #include <string>

 #include <cstdlib>

 #include <cstring>

 #include <iostream>

 #include <algorithm>

 #define query QUERY

 #define LL long long

 #define Max(a, b) ((a) > (b) ? (a) : (b))

 #define Min(a, b) ((a) < (b) ? (a) : (b))

 using namespace std;

 const int N = ;

 void read(int &x) {

     char ch; bool flag = ;

     for (ch = getchar(); !isdigit(ch) && ((flag |= (ch == '-')) || ); ch = getchar());

     for (x = ; isdigit(ch); x = (x<<)+(x<<)+ch-, ch = getchar());

     x *= -*flag;

 }

 int n, r, x, y, v;

 int mp[N+][N+];

 void work() {

     read(n), read(r);

     for (int i = ; i <= n; i++) {

         read(x), read(y), read(v);

         mp[x+][y+] = v;

     }

     for (int i = ; i <= N+; i++)

         for (int j = ; j <= N+; j++)

             mp[i][j] += mp[i][j-]+mp[i-][j]-mp[i-][j-];

     int ans = ;

     for (int i = r; i <= N+; i++)

         for (int j = r; j <= N+; j++)

             ans = Max(ans, mp[i][j]-mp[i-r][j]-mp[i][j-r]+mp[i-r][j-r]);

     printf("%d\n", ans);

 }

 int main() {

     work();

     return ;

 }