/**
 *    author:  cody
 *    created: 10.08.2024 05:10
 **/

#include <bits/stdc++.h>

using namespace std;
#define ll long long 
const ll nmax = 1e6 + 1;
ll n, w, h, mx = -1e18, cnt = -1e18, m;
signed main()
{
    cin >> n >> m >> w >> h;
    ll a[n + 1], b[m + 1], x;
    a[0] = b[0] = 0;
    for (ll i = 1; i <= n; ++i) cin >> x, a[i] = a[i - 1] + x * h;
    for (ll i = 1; i <= m; ++i) cin >> x, b[i] = b[i - 1] + x * w;
    for (ll i = w; i <= n; ++i) mx = max(mx , a[i] - a[i - w]);
    for (ll i = h; i <= m; ++i) cnt = max(cnt , b[i] - b[i - h]);
    cout << mx + cnt;
}

#danglam228

#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 5;
int m, n, w, h;
int main() {
        ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    //freopen(".INP", "r", stdin);
    //freopen(".OUT", "w", stdout);
    cin >> m >> n >> w >> h;

    int a[105], b[105];
    for (int i = 0; i < m; i++) {
        cin >> a[i];
    }
    for (int j = 0; j < n; j++) {
        cin >> b[j];
    }
    int f[105][105];
    for (int i = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
            f[i][j] = a[i] + b[j];
        }
    }
    int d1 = 0;
    for (int i = 0; i <= m - h; i++) {
        for (int j = 0; j <= n - w; j++) {
            int d2 = 0;
            for (int k = 0; k < h; k++) {
                for (int t = 0; t < w; t++) {
                    d2 += f[i + k][j + t];
                }
            }
            d1 = max(d1, d2);
        }
    }
    cout << d1 << endl;
    return 0;
}