#include <iostream>
#include <algorithm>

#define fname "."
#define ll long long

using namespace std;
int n, m, w, h;
ll a[100005], b[100005];

int main() {
    if(fopen(fname"inp", "r")) {
        freopen(fname"inp", "r", stdin);
        freopen(fname"out", "w", stdout);
    }
    cin>>n>>m>>w>>h;
    for(int i=1; i<=n; ++i) cin>>a[i], a[i]+=a[i-1];
    for(int i=1; i<=m; ++i) cin>>b[i], b[i]+=b[i-1];
    
    ll mxa=-1e18, mxb=-1e18;
    
    ll res=-1e18;
    if(w<=n && h<=m) {
        for(int i=w; i<=n; ++i) mxa=max(mxa, a[i]-a[i-w]);
        for(int i=h; i<=m; ++i) mxb=max(mxb, b[i]-b[i-w]);
        res=max(res, w*mxa+h*mxb);
    }
    if(h<=n && w<=m) {
        mxa=-1e18, mxb=-1e18;
        for(int i=h; i<=n; ++i) mxa=max(mxa, a[i]-a[i-w]);
        for(int i=w; i<=m; ++i) mxb=max(mxb, b[i]-b[i-w]);
        res=max(res, h*mxa+w*mxb);
    }
    cout<<res;
}
/*

*/