1 #include <iostream>
2 #include <cstring>
3 #include <cstdio>
4 using namespace std;
5 const int maxn=1510;
6 int Ul[maxn][maxn],Ur[maxn][maxn];
7 int Dl[maxn][maxn],Dr[maxn][maxn];
8 int a[maxn][maxn];
9
10 int sum(int x,int y,int k)
11 {
12 if(x<k||y<k)return 0;
13 return a[x][y]-a[x-k][y]-a[x][y-k]+a[x-k][y-k];
14 }
15
16 void Pre_Solve(int R,int C,int K)
17 {
18 for(int i=K;i<=R;i++)
19 for(int j=K;j<=C;j++){
20 int S=sum(i,j,K);
21 Ul[i][j]=S;
22 Ur[i][j-K+1]=S;
23 Dl[i-K+1][j]=S;
24 Dr[i-K+1][j-K+1]=S;
25 }
26
27 for(int i=1;i<=R;i++)
28 for(int j=1;j<=C;j++)
29 Ul[i][j]=max(Ul[i][j],max(Ul[i-1][j],Ul[i][j-1]));
30
31 for(int i=1;i<=R;i++)
32 for(int j=C;j>=1;j--)
33 Ur[i][j]=max(Ur[i][j],max(Ur[i-1][j],Ur[i][j+1]));
34
35 for(int i=R;i>=1;i--)
36 for(int j=1;j<=C;j++)
37 Dl[i][j]=max(Dl[i][j],max(Dl[i+1][j],Dl[i][j-1]));
38
39 for(int i=R;i>=1;i--)
40 for(int j=C;j>=1;j--)
41 Dr[i][j]=max(Dr[i][j],max(Dr[i+1][j],Dr[i][j+1]));
42 }
43 int ans=0;
44 void Solve(int R,int C,int K)
45 {
46 for(int i=1;i<=R;i++){
47 for(int j=1;j<=C;j++){
48 ans=max(ans,Ul[i][C]+Dl[i+1][j]+Dr[i+1][j+1]);
49 ans=max(ans,Ul[i][j]+Ur[i][j+1]+Dr[i+1][1]);
50 ans=max(ans,Ul[i][j]+Dl[i+1][j]+Dr[1][j+1]);
51 ans=max(ans,Ul[R][j]+Ur[i][j+1]+Dr[i+1][j+1]);
52 }
53 }
54 for(int i=2*K;i<R;i++){
55 int MaxS=0;
56 for(int j=1;j<=C;j++)
57 MaxS=max(MaxS,sum(i,j,K));
58 ans=max(ans,Ul[i-K][C]+MaxS+Dr[i+1][1]);
59 }
60 for(int j=2*K;j<C;j++){
61 int MaxS=0;
62 for(int i=1;i<=R;i++)
63 MaxS=max(MaxS,sum(i,j,K));
64 ans=max(ans,Ul[R][j-K]+MaxS+Dr[1][j+1]);
65 }
66 }
67 int main()
68 {
69 #ifndef ONLINE_JUDGE
70 freopen("oil.in","r",stdin);
71 freopen("oil.out","w",stdout);
72 #endif
73 int R,C,K;
74 scanf("%d%d%d",&R,&C,&K);
75 for(int i=1;i<=R;i++)
76 for(int j=1;j<=C;j++){
77 scanf("%d",&a[i][j]);
78 a[i][j]+=a[i-1][j]+a[i][j-1]-a[i-1][j-1];
79 }
80 Pre_Solve(R,C,K);
81 Solve(R,C,K);
82 printf("%d\n",ans);
83 }
