#include <stdio.h>

#define maxn 510

int n,m,r,t,now,total,flag2,data[maxn][maxn];
long ans;
FILE *f1,*f2;

int attack(int x,int y)
{
	int i,j,max_x,max_y,left,right,up,down,flag;
	left=y-r;
	if (left<0)
		left=0;
	right=y+r;
	if (right>=m)
		right=m-1;
	up=x-r;
	if (up<0)
		up=0;
	down=x+r;
	if (down>=n)
		down=n-1;
	max_x=max_y=500;
	data[max_x][max_y]=0;
	flag=0;
	for (i=up;i<=down;i++)
		for (j=left;j<=right;j++)
		{
			if (data[i][j]>data[max_x][max_y])
			{
				max_x=i;
				max_y=j;
				flag=1;
			}
		}
	if (flag==0)
		return 0;
	return max_x*m+max_y;
}

void search(int x,int y,int time,int point)
{
	int zan,a,b;
	if (time>=t)
	{
		if (point>ans)
			ans=point;
		if (now>=total)
			flag2=1;
		return;
	}
	if (flag2)
		return;
	zan=attack(x,y);
	if (zan!=0)
	{
		a=zan/m;
		b=zan%m;
		zan=data[a][b];
		data[a][b]=0;
		now++;
		search(x,y,time+1,point+zan);
		data[a][b]=zan;
		now--;
	}
	if (x+1<n)
		search(x+1,y,time+1,point);
	if (y+1<m)
		search(x,y+1,time+1,point);
}

void run(void)
{
	flag2=0;
	search(0,0,0,0);
}

void ini(void)
{
	int i,j;
	fscanf(f1,"%d%d%d%d",&n,&m,&r,&t);
	for (i=0;i<n;i++)
		for (j=0;j<m;j++)
		{
			fscanf(f1,"%d",&data[i][j]);
			if (data[i][j]!=0)
				total++;
		}
}

int main(void)
{
	f1=fopen("gametk.in","r");
	f2=fopen("gametk.out","w");
	ini();
	run();
	fprintf(f2,"%ld\n",ans);
	fclose(f1);fclose(f2);
	return 0;
}