#include<stdio.h>
#include<algorithm>
#include<string.h>
#include<iostream>
#define N 1005
using namespace std;

int C[N][N];
int n,m,x,y;
int lowbit(int x1){
    return x1&(-x1);
}

int update(int x1,int y1,int value){
    for(int i=x1;i<=n;i+=lowbit(i)){
        for(int j=y1;j<=m;j+=lowbit(j)){
            C[i][j]+=value;
        }
    }
}
int getSum(int x1,int y1){
    int value = 0;
    for(int i=x1;i>=1;i-=lowbit(i)){
        for(int j=y1;j>=1;j-=lowbit(j)){
            value+=C[i][j];
        }
    }
    return value;
}
int main()
{
    int tcase;
    scanf("%d",&tcase);
    while(tcase--){
        memset(C,0,sizeof(C));
        scanf("%d%d%d%d",&n,&m,&x,&y);
        int num;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=m;j++){
                scanf("%d",&num);
                update(i,j,num);
            }
        }
        int mx = -1;
        for(int i=1;i<=n;i++){
            if(i+x-1>n) continue;
            for(int j=1;j<=m;j++){
                if(j+y-1>m) continue;
                int x1 = i;
                int x2 = i+x-1;
                int y1 = j;
                int y2 = j+y-1;
                int sum = getSum(x2,y2)-getSum(x1-1,y2)-getSum(x2,y1-1)+getSum(x1-1,y1-1);  
                //printf("%d\n",sum);
                if(sum>mx) mx = sum;
            }
        }
        printf("%d\n",mx);
    }
    return 0;
}