OpenCup XV: Grand Prix of America F

import java.io.*;
import java.util.*;

public class F {
    FastScanner in;
    PrintWriter out;

    class Edge {
        int to;
        double flow, cap;

        public Edge(int to, double cap) {
            super();
            this.to = to;
            this.cap = cap;
        }

        Edge rev;

        @Override
        public String toString() {
            return "Edge [to=" + to + ", flow=" + flow + ", cap=" + cap + "]";
        }

    }

    class Flow {
        ArrayList<Edge>[] g;
        int[] h;
        int[] cur;
        int[] q;
        int n;

        Flow(int n) {
            this.n = n;
            g = new ArrayList[n];
            for (int i = 0; i < n; i++) {
                g[i] = new ArrayList<>();
            }
            h = new int[n];
            q = new int[n];
            cur = new int[n];
        }

        void clean() {
            for (int i = 0; i < n; i++) {
                for (Edge e : g[i]) {
                    e.flow = 0;
                }
            }
        }

        Edge addEdge(int fr, int to, double cap) {
            Edge e1 = new Edge(to, cap);
            Edge e2 = new Edge(fr, 0);
            e1.rev = e2;
            e2.rev = e1;
            g[fr].add(e1);
            g[to].add(e2);
            return e1;
        }

        boolean bfs() {
            int qIt = 0, qSz = 1;
            Arrays.fill(h, -1);
            q[0] = 0;
            h[0] = 0;
            while (qIt < qSz) {
                int v = q[qIt++];
                for (Edge e : g[v]) {
                    if (e.flow < e.cap) {
                        if (h[e.to] == -1) {
                            h[e.to] = h[v] + 1;
                            q[qSz++] = e.to;
                        }
                    }
                }
            }
            return h[n - 1] != -1;
        }

        double dfs(int v, double fl) {
            if (v == n - 1 || fl == 0) {
                return fl;
            }
            for (; cur[v] < g[v].size(); cur[v]++) {
                Edge e = g[v].get(cur[v]);
                if (h[e.to] == h[v] + 1) {
                    double add = dfs(e.to, Math.min(e.cap - e.flow, fl));
                    if (add == 0) {
                        continue;
                    }
                    e.flow += add;
                    e.rev.flow -= add;
                    return add;
                }
            }
            return 0;
        }

        double getFlow() {
            double res = 0;
            while (bfs()) {
                Arrays.fill(cur, 0);
                while (true) {
                    double xx = dfs(0, Double.MAX_VALUE);
                    if (xx == 0) {
                        break;
                    }
                    res += xx;
                }
            }
            return res;
        }
    }

    void solve() {
        int n = in.nextInt();
        int m = in.nextInt();
        int w = in.nextInt();
        int h = in.nextInt();
        double[] maxColor = new double[m];
        for (int i = 0; i < m; i++) {
            maxColor[i] = in.nextDouble();
        }
        double last = 0;
        double[] ww = new double[n];
        for (int i = 0; i < n - 1; i++) {
            double cur = in.nextDouble();
            ww[i] = cur - last;
            last = cur;
        }
        ww[n - 1] = w - last;
        double[][] min = new double[n][m];
        double[][] max = new double[n][m];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                min[i][j] = in.nextDouble();
            }
        }
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                max[i][j] = in.nextDouble();
            }
        }
        Flow f = new Flow(2 + n + m);
        Edge[] toSections = new Edge[n];
        for (int i = 0; i < n; i++) {
            toSections[i] = f.addEdge(0, 1 + i, 0);
        }
        for (int i = 0; i < m; i++) {
            double sumColor = 0;
            for (int j = 0; j < n; j++) {
                sumColor += min[j][i];
            }
            f.addEdge(1 + n + i, 1 + n + m, maxColor[i] - sumColor);
        }
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                f.addEdge(1 + i, 1 + n + j, max[i][j] - min[i][j]);
            }
        }
        double left = 0, right = h;
        double maxH = 0;
        double[] minH = new double[n];
        for (int i = 0; i < n; i++) {
            double sum = 0;
            for (int j = 0; j < m; j++) {
                sum += min[i][j];
            }
            minH[i] = sum / ww[i];
            maxH = Math.max(maxH, sum / ww[i]);
        }
        for (int it = 0; it < 66; it++) {
            double mid = (left + right) / 2;
            f.clean();
            for (int i = 0; i < n; i++) {
                double curH = Math.max(minH[i], maxH - mid) - minH[i];
                toSections[i].cap = curH * ww[i];
            }
            f.getFlow();
            boolean ok = true;
            for (int i = 0; i < n; i++) {
                if (toSections[i].flow != toSections[i].cap) {
                    ok = false;
                    break;
                }
            }
            if (ok) {
                right = mid;
            } else {
                left = mid;
            }
        }
        out.printf(Locale.US, "%.3f\n", (left + right) / 2);
    }

    void run() {
        try {
            in = new FastScanner(new File("F.in"));
            out = new PrintWriter(new File("F.out"));

            solve();

            out.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

    void runIO() {

        in = new FastScanner(System.in);
        out = new PrintWriter(System.out);

        solve();

        out.close();
    }

    class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner(File f) {
            try {
                br = new BufferedReader(new FileReader(f));
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }

        public FastScanner(InputStream f) {
            br = new BufferedReader(new InputStreamReader(f));
        }

        String next() {
            while (st == null || !st.hasMoreTokens()) {
                String s = null;
                try {
                    s = br.readLine();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (s == null)
                    return null;
                st = new StringTokenizer(s);
            }
            return st.nextToken();
        }

        boolean hasMoreTokens() {
            while (st == null || !st.hasMoreTokens()) {
                String s = null;
                try {
                    s = br.readLine();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (s == null)
                    return false;
                st = new StringTokenizer(s);
            }
            return true;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }
    }

    public static void main(String[] args) {
        new F().runIO();
    }
}