#include <iostream>

 #include <cstring>

 #include <algorithm>

 using namespace std;

 int n, m;

 const int maxn = 1e2 + ;

 int maze[maxn][maxn], dp[maxn][maxn], dir[][] = {{,},{-,},{,},{,-}};

 int dfs(int x, int y) {

     int ans = ;

     if(!dp[x][y]) {

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

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

                 int dx = x + dir[j][] * i;

                 int dy = y + dir[j][] * i;

                 if(dx <  || dy <  || dx > n || dy > n) continue;

                 if(maze[dx][dy] > maze[x][y]) ans = max(ans, dfs(dx, dy));

             }

         }

         dp[x][y] = ans + maze[x][y];

     }

     return dp[x][y];

 }

 int main () {

     ios :: sync_with_stdio (false);

     while(cin >> n >> m) {

         memset(dp, , sizeof dp);

         if(n == - && m == -) break;

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

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

                 cin >> maze[i][j];

         cout << dfs(, ) << endl;

     }

     return ;

 }