1 #include <iostream>
 2 #include <cstdio>
 3 using namespace std;
 4 #define N 1005
 5 int arr[N][N];
 6 
 7 int main()
 8 {
 9     int t, m, n, x, y;
10     int i, j, k, l, sum, max;
11     scanf("%d",&t);
12     while(t--)
13     {
14         scanf("%d%d%d%d",&m,&n,&x,&y);
15         memset(arr,0,sizeof(arr));
16         for(i=1; i<=m; i++)
17             for(j=1; j<=n; j++)
18             {
19                 scanf("%d",&arr[i][j]);
20                 arr[i][j] += arr[i][j-1];    //每一列等于前面所有列对应的和
21             }
22         sum = 0;
23         max = 0;
24         for(i=x; i<=m; i++)
25         {
26             for(j=1; j<=n-y; j++)
27             {
28                 for(k=j; k<j+y; k++)
29                     sum += (arr[k][i]-arr[k][i-x]);        //括号里的所有可能得x列的和
30                 if(sum>max)
31                     max = sum;
32                 sum = 0;
33             }
34         }
35         printf("%d\n",max);
36     }
37     return 0;
38 }