1 #include<bits/stdc++.h>
 2 using namespace std;
 3 typedef unsigned int ui;
 4 typedef long long ll;
 5 typedef unsigned long long ull;
 6 #define pf printf
 7 #define prime1 1e9+7
 8 #define prime2 1e9+9
 9 #define scand(x) scanf("%llf",&x)
10 #define f(i,a,b) for(int i=a;i<=b;i++)
11 #define scan(a) scanf("%d",&a)
12 #define dbg(args) cout<<#args<<":"<<args<<endl;
13 #define pb(i) push_back(i)
14 #define ppb(x) pop_back(x)
15 #define maxn 1005
16 int n,k,t;
17 int Map[maxn][maxn],dp[maxn][maxn];
18 int dir[][2]={{0,1},{0,-1},{-1,0},{1,0}};
19 bool ok(int x,int y)
20 {
21     if(x<0||x>=n||y<0||y>=n)return false;
22     return true;
23 }
24 int dfs(int x,int y)
25 {
26     if(dp[x][y])return dp[x][y];
27     int temp=0;
28     int M=0;
29     f(i,0,3)
30         f(j,1,k)
31         {
32             int xx=x+dir[i][0]*j;
33             int yy=y+dir[i][1]*j;
34             if(ok(xx,yy)&&Map[xx][yy]>Map[x][y])
35             {
36                 temp=dfs(xx,yy);
37                 if(temp>dp[xx][yy])dp[xx][yy]=temp;
38                 if(dp[xx][yy]>M)M=dp[xx][yy];
39             }
40         }
41         
42     return dp[x][y]=Map[x][y]+M;
43 }
44 int main()
45 {
46     std::ios::sync_with_stdio(false);
47     while(scanf("%d%d",&n,&k)==2&&!(k==-1&&n==-1))
48     {
49         memset(dp,0,sizeof(dp));
50         f(i,0,n-1)
51             f(j,0,n-1)
52             {
53                 scan(Map[i][j]);
54             }
55         dp[0][0]=dfs(0,0);
56         pf("%d\n",dp[0][0]);
57     }
58  }