1 #include <cstdio>
 2 #include <cmath>
 3 #include <cstring>
 4 #include <cstdlib>
 5 #include <queue>
 6 #include <stack>
 7 #include <vector>
 8 #include <iostream>
 9 #include "algorithm"
10 using namespace std;
11 typedef long long LL;
12 const int MAX=505;
13 int n,m,A,B;
14 int s[MAX][MAX];
15 void init(){
16     int i,j,k;
17     scanf("%d%d%d%d",&n,&m,&A,&B);
18     memset(s,0,sizeof(s));
19     for (i=1;i<=n;i++){
20         for (j=1;j<=m;j++){
21             scanf("%d",&k);
22             s[i][j]=s[i-1][j]+s[i][j-1]-s[i-1][j-1]+k;
23         }
24     }
25 }
26 int squ(int x,int y,int a,int b){
27     return s[x][y]-s[a][y]-s[x][b]+s[a][b];
28 }
29 bool feasible(int x){
30     int i,j,last1=0,last2;
31     int a=0,b;
32     for (i=1;i<=n;i++){
33         b=0;
34         last2=0;
35         for (j=1;j<=m;j++){
36             if (squ(i,j,last1,last2)>=x){
37                 b++;
38                 last2=j;
39             }
40         }
41         if (b>=B) a++,last1=i;
42     }
43     return (a>=A);
44 }
45 int main(){
46     freopen ("aiur.in","r",stdin);
47     freopen ("aiur.out","w",stdout);
48     init();int i,j;
49     int low,high,mid;
50     low=1,high=s[n][m]/(A*B);
51     while (low<=high){
52         mid=(low+high)>>1;
53         if (feasible(mid))
54          low=mid+1;
55         else
56          high=mid-1;
57     }
58     printf("%d",low-1);
59     return 0;
60 }