#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
long long int sol[100], n, m, r, c, maxx, a[1000][1000];
long long int s;
ifstream fin("elimin.in");
ofstream fout("elimin.out");
void calcmax()
{
    s = 0;
    for (int i = 1; i <= r; i++)
    {
        for (int j = 1; j <= c; j++)
            s += a[i][j];
    }
    if (s > maxx)
        maxx = s;
}

bool ok(int k)
{
    for (int i = 1; i < k; i++)
    {
        if (sol[i] == sol[k])
            return 0;
    }
    return 1;
}

void back(int k)
{
    for (int i = 1; i <= m; i++)
    {
        sol[k] = i;
        if (ok(k))
        {
            if (k == r)
                calcmax();
            else back(k + 1);
        }
    }
}

int main()
{
    fin >> m >> n >> r >> c;
    c = n - c;
    r = m - r;
    for (int i = 1; i <= m; i++)
        for (int j = 1; j <= n; j++)
            fin >> a[i][j];
    back(1);
    fout << maxx;
    return 0;
}