#include<cstdio>
#include<vector>
#include<cmath>
#include<cstring>
#include<algorithm>
using namespace std;
typedef long long ll;
const ll maxn = 25;
int n, m, x, y, mp[maxn][maxn], t1, t2;
inline void read(int &ret)
{
char c;
do {
c = getchar();
} while (c < '0' || c > '9');
ret = c - '0';
while ((c = getchar()) >= '0' && c <= '9')
ret = ret * 10 + (c - '0');
}
struct DLX
{
#define maxn 10005
#define F(i,A,s) for (int i=A[s];i!=s;i=A[i])
int L[maxn], R[maxn], U[maxn], D[maxn];
int row[maxn], col[maxn], ans[maxn], cnt[maxn];
int n, m, num, sz;
void add(int now, int l, int r, int u, int d, int x, int y)
{
L[now] = l; R[now] = r; U[now] = u;
D[now] = d; row[now] = x; col[now] = y;
}
void reset(int n, int m, int x)
{
if (x) num = 0x7FFFFFFF; else num = 0;
this->n = n; this->m = m;
for (int i = 0; i <= m; i++)
{
add(i, i - 1, i + 1, i, i, 0, i);
cnt[i] = 0;
}
L[0] = m; R[m] = 0; sz = m + 1;
}
void insert(int x, int y)
{
int ft = sz - 1;
if (row[ft] != x)
{
add(sz, sz, sz, U[y], y, x, y);
U[D[sz]] = sz; D[U[sz]] = sz;
}
else
{
add(sz, ft, R[ft], U[y], y, x, y);
R[L[sz]] = sz; L[R[sz]] = sz;
U[D[sz]] = sz; D[U[sz]] = sz;
}
++cnt[y]; ++sz;
}
//精确覆盖
void remove(int now)
{
R[L[now]] = R[now];
L[R[now]] = L[now];
F(i, D, now) F(j, R, i)
{
D[U[j]] = D[j];
U[D[j]] = U[j];
--cnt[col[j]];
}
}
void resume(int now)
{
F(i, U, now) F(j, L, i)
{
D[U[j]] = j;
U[D[j]] = j;
++cnt[col[j]];
}
R[L[now]] = now;
L[R[now]] = now;
}
int dfs(int x)
{
if (!R[0]) return 1;
int now = R[0];
F(i, R, 0) if (cnt[now]>cnt[i]) now = i;
remove(now);
F(i, D, now)
{
ans[x] = row[i];
F(j, R, i) remove(col[j]);
if (dfs(x + 1)) return 1;
F(j, L, i) resume(col[j]);
}
resume(now);
return 0;
}
//精确覆盖
//重复覆盖
void Remove(int now)
{
F(i, D, now)
{
L[R[i]] = L[i];
R[L[i]] = R[i];
}
}
void Resume(int now)
{
F(i, U, now) L[R[i]] = R[L[i]] = i;
}
int vis[maxn];
int flag[maxn];
int A()
{
int dis = 0;
F(i, R, 0) vis[i] = 0;
F(i, R, 0) if (!vis[i])
{
dis++; vis[i] = 1;
F(j, D, i) F(k, R, j) vis[col[k]] = 1;
}
return dis;
}
void Dfs(int x)
{
if (!R[0]) num = min(num, x);
else if (x + A()<num)
{
int now = R[0];
F(i, R, 0) if (cnt[now]>cnt[i]) now = i;
F(i, D, now)
{
Remove(i); F(j, R, i) Remove(j);
Dfs(x + 1);
F(j, L, i) Resume(j); Resume(i);
}
}
}
//重复覆盖
}dlx;
int main()
{
//read(T);
while (scanf("%d%d", &n, &m) == 2)
{
t1 = t2 = 0;
for (int i = 1; i <= n; ++i)
for (int j = 1; j <= m; ++j)
{
scanf("%d", &mp[i][j]);
t2 += mp[i][j];
if (mp[i][j]) mp[i][j] = t2;
}
scanf("%d%d", &x, &y);
t1 = (n - x + 1)*(m - y + 1);
dlx.reset(t1, t2, 1);
t1 = 0;
for (int i = 1; i + x - 1 <= n; i++)
for (int j = 1; j + y - 1 <= m; j++)
{
t1++;
for (int x1 = 0; x1 < x; x1++)
for (int y1 = 0; y1 < y; y1++)
if (mp[i + x1][j + y1]) dlx.insert(t1, mp[i + x1][j + y1]);
}
dlx.Dfs(0);
printf("%d\n", dlx.num);
}
return 0;
}
