1 //2017-09-24
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <iostream>
 5 #include <algorithm>
 6 
 7 using namespace std;
 8 
 9 const int N = 1010;
10 
11 int a[N][N], dp[N][N], n, m, x, y;
12 
13 int main()
14 {
15     int T;
16     scanf("%d", &T);
17     while(T--){
18         scanf("%d%d%d%d", &n, &m, &x, &y);
19         for(int i = 0; i < n; i++)
20           for(int j = 0; j < m; j++){
21               scanf("%d", &a[i][j]);
22               dp[i][j] = a[i][j];
23           }
24         for(int i = 1; i < n; i++)
25           for(int j = 0; j < m; j++)
26             dp[i][j] += dp[i-1][j];
27         for(int j = 1; j < m; j++)
28           for(int i = 0; i < n; i++)
29             dp[i][j] += dp[i][j-1];
30         int ans = 0;
31         for(int i = x-1; i < n; i++)
32           for(int j = y-1; j < m; j++){
33               int a = i-x+1;
34               int b = j-y+1;
35               int tmp = dp[i][j];
36               if(a-1>=0)tmp -= dp[a-1][j];
37               if(b-1>=0)tmp -= dp[i][b-1];
38               if(a-1>=0 && b-1>=0)tmp += dp[a-1][b-1];
39               ans = max(ans, tmp);
40           }
41         printf("%d\n", ans);
42     }
43 
44     return 0;
45 }