1 1 2 2
1000000000 1000000000
1
 1 1 1000000000 1000000000
100 1000000000
1
 1 1 10 18
5 6
5
 2 1 1000000000 2000000000
111 999999999
101 999999998
1
 4 13 400 600
13 30
1 19
1 160
1 113
58 73 15 319 194 362 128 157 336 162 77 90 96
 1 15 100 200
283 8
30 58 16 45 80 82 55 95 24 23 86 28 51 47 20
 3 2 300 400
24 68
13 65
15 113
127 177
 1 1 2 1
1 10
1
 4 2 7 15
10 9
4 4
9 3
4 10
1 6
 2 1 1000000000 2000000000
111 1000000000
101 1000000000
5
 2 1 1000000000 2000000000
111 999999998
101 999999998
1
 1 1 1000000000 1000000000
1 1000000000
1

1000000000
 -1
 5
 111
 1
 -1
 -1
 -1
 4
 101
 -1
 -1

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

public class Main2 {

    static String file = "game";
    static ArrayList<Integer>[] a;
    static byte[] dist, DIST;
    static boolean[] visited, VISITED;
    static boolean vrunishki;

    static void code() {
        int[][] a = new int[sc.nextInt()][2];
        int[] aa = new int[sc.nextInt() + 2];
        aa[aa.length - 1] = sc.nextInt();
        int t = sc.nextInt();
        int res = Integer.MAX_VALUE;
        for (int i = 0; i < a.length; i++) {
            a[i][0] = sc.nextInt();
            a[i][1] = sc.nextInt();
        }
        for (int i = 1; i < aa.length - 1; i++) {
            aa[i] = sc.nextInt();
        }
        Arrays.sort(aa);
        for (int i = 0; i < a.length; i++) {
            if (a[i][0] < res) {
                int tt = 0;
                int j = 1;
                while (tt < t && j < aa.length) {
                    if (a[i][1] < aa[j] - aa[j - 1]) {
                        break;
                    } else {
                        if (a[i][1] > 2 * (aa[j] - aa[j - 1])) {
                            tt += aa[j] - aa[j - 1];
                        } else {
                            tt += 3 * (aa[j] - aa[j - 1]) - a[i][1];
                        }
                        j++;
                    }
                }
                if (j == aa.length && t >= tt) {
                    res = Math.min(a[i][0], res);
                }
            }
        }
        pw.print(res);
    }

    static void DFS(int v) {
        visited[v] = true;
        int size = a[v].size();
        for (int i = 0; i < size; i++) {
            if (!visited[a[v].get(i)]) {
                if (VISITED[a[v].get(i)]) {
                    if (!VISITED[v]) {
                        VISITED[v] = true;
                        dist[v] = (byte) ((dist[a[v].get(i)] + 2) / 3);
                    } else {
                        if ((dist[v] + 1) % 3 != dist[a[v].get(i)]) {
                            vrunishki = true;
                            return;
                        }
                    }
                } else {
                    if (!VISITED[v]) {
                        DIST[a[v].get(i)] = (byte) ((DIST[v] + 1) % 3);
                        DFS(a[v].get(i));
                        if (vrunishki) {
                            return;
                        }
                        if (VISITED[a[v].get(i)]) {
                            i = -1;
                        }
                    } else {
                        DIST[a[v].get(i)] = (byte) ((DIST[v] + 1) % 3);
                        dist[a[v].get(i)] = (byte) ((dist[v] + 1) % 3);
                        DFS(a[v].get(i));
                        if (vrunishki) {
                            return;
                        }
                        if (VISITED[a[v].get(i)]) {
                            i = -1;
                        }
                    }
                }
            } else {
                if ((DIST[v] + 1) % 3 != DIST[a[v].get(i)]) {
                    vrunishki = true;
                    return;
                }
            }
        }
    }

    //static int R;

    public static void main(String[] args) throws IOException {

        sc = new FScanner(/*new FileInputStream(new File(file + ".in"))*/ System.in);
        pw = new PrintWriter(new BufferedOutputStream(/*new FileOutputStream(file + ".out")*/ System.out) /*FileWriter(new File(file + ".out"))*/);
        code();
        pw.close();
    }

    static PrintWriter pw;
    static FScanner sc;

    static class Matrica {
        int a, b, c, d;
    }

    static class NodeOtreskov {
        Matrica[] a;
        int size;
        long l, r;
        Matrica neytral;

        NodeOtreskov(int n) {
            size = 1;
            while (size < n) {
                size *= 2;
            }
            a = new Matrica[2 * size - 1];
            neytral = new Matrica();
            neytral.a = 1;
            neytral.d = 1;
            for (int i = 0; i < a.length; i++) {
                a[i] = neytral;
            }
        }


    }

    static class FScanner {
        private BufferedReader br;
        private StringTokenizer tokenizer;

        public FScanner(InputStream stream) throws FileNotFoundException {
            br = new BufferedReader(new InputStreamReader(stream));
        }

        public boolean hasNext() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    String s = br.readLine();
                    if (s == null) {
                        return false;
                    }
                    tokenizer = new StringTokenizer(s);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.hasMoreTokens();
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public String nextLine() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    return br.readLine();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken("\n");
        }

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

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

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