#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

const int N = 110;

int n, m;
int w[N][N];
int f[N][N];
int dx[] = {-1, 0, 1, 0}, dy[] = {0, 1, 0, -1};

int dfs(int x, int y)
{
    if (f[x][y]) return f[x][y];

    int s = 0;
    for (int i = 0; i < 4; i ++ ) 
        for (int j = 1; j <= m; j ++ )
        {
            int a = x + dx[i] * j, b = y + dy[i] * j;
            if (a < 0 || a >= n || b < 0 || b >= n) continue;
            if (w[a][b] <= w[x][y]) continue;
            s = max(s, dfs(a, b));
        }

    return f[x][y] = w[x][y] + s;
}

int main()
{
    while (cin >> n >> m, ~n && ~m)
    {
        for (int i = 0; i < n; i ++ ) 
            for (int j = 0; j < n; j ++ )
                cin >> w[i][j], f[i][j] = 0;

        cout << dfs(0, 0) << endl;
    }

    return 0;
}