// __   _   _   _   _____   _   _   _____   _   _       ___
//|  \ | | | | | | /  ___| | | | | /  ___/ | | | |     /   |
//|   \| | | | | | | |     | | | | | |___  | |_| |    / /| |
//| |\   | | | | | | |  _  | | | | \___  \ |  _  |   / / | |
//| | \  | | |_| | | |_| | | |_| |  ___| | | | | |  / /  | |
//|_|  \_| \_____/ \_____/ \_____/ /_____/ |_| |_| /_/   |_|

#include<iostream>
#include<fstream>
#include<stdio.h>
#include<cstdio>
#include<stdlib.h>
#include<string>
#include<string.h>
#include<ctype.h>
#include<algorithm>
#include<cmath>
#include<set>
#include<queue>
#include<stack>
#include<iomanip>
#include<vector>
#include<map>
#define PB(x) push_back(x)
#define MP(x, y) make_pair(x, y)
#define ff first
#define ss second
#define ll long long
#define pii pair< int, int >
#define MEM(p, v) memset(p, v, sizeof(p))
#define READ(f) freopen(f, "r", stdin)
#define WRITE(f) freopen(f, "w", stdout)
#define S system("pause")
#define R return(0)
#define INF int(1e9)
#define MAX_5 int(1e5+5)
#define MAX_6 int(1e6+6)
#define ll long long
using namespace std;
int a[3005][3005],d[3005][3005],i,m,ans,k,l,j,r,q,o,x,n,ma,mi,w,c;
string s;
int get(int i,int j,int ii,int jj)
{
 return d[ii][jj]-d[ii][j-1]-d[i-1][jj]+d[i-1][j-1];
}
int go(int k)
{
    for(q=1;q<=n;q++)
    for(o=1;o<=m;o++)
        d[q][o]=d[q-1][o]+d[q][o-1]-d[q-1][o-1]+(a[q][o]>k?1:(a[q][o]==k?0:-1));

        /*
        cout<<k<<endl;


    for(q=1;q<=n;q++){
    for(o=1;o<=m;o++)cout<<d[q][o]<<" ";cout<<endl;}
    cout<<"---"<<endl;
        */
        int f=1;
    for(q=1;q<=n-w+1;q++)
    for(o=1;o<=m-c+1;o++)
    {
        int u=get(q,o,q+w-1,o+c-1);
        if(u<0)return -1;
        if(u==0)f=0;
    }
    return f;
}
main()
{
          cin>>n>>m>>w>>c;
          for(i=1;i<=n;i++)
          for(j=1;j<=m;j++)scanf("%d",&a[i][j]);

          l=1;r=n*m;



          while(l<=r)
          {
                    int mid=l+r;mid/=2;
                    x=go(mid);
                    if(x==-1)r=mid-1;else
                    if(x==1) l=mid+1;else
                    if(x==0){printf("%d\n",mid);break;}
          }
}