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 javafx.util.Pair;

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

public class Main {

    private static myScanner sc;
    private static PrintWriter pw;

    private static final boolean defaultInAndOutPut = true;

    private static final int numberOfTests = 1;

    private static final String nameOfInAndOutFile = "";
    private static final String fullNameInputFile = nameOfInAndOutFile + ".in";
    private static final String fullNameOutputFile = nameOfInAndOutFile + ".out";

    public static void main(String[] args) throws IOException {
        if (defaultInAndOutPut) {
            setDefaultInAndOutPut();
        } else {
            setInAndOutPutFromFile();
        }
        for (int test = 1; test <= numberOfTests; test++) {
            solve();
            pw.flush();
        }

        pw.close();
    }

    private static void setDefaultInAndOutPut() {
        sc = new myScanner(new BufferedReader(new InputStreamReader(System.in)));
        pw = new PrintWriter(System.out);
    }

    private static void setInAndOutPutFromFile() throws IOException {
        sc = new myScanner(new BufferedReader(new FileReader(new File(fullNameInputFile))));
        pw = new PrintWriter(new File(fullNameOutputFile));
    }

    private static final int intINF = Integer.MAX_VALUE;
    private static final int MOD = 1000000007;
    private static final long longINF = Long.MAX_VALUE;

    private static void solve() {
        int n = sc.nextInt(), k = sc.nextInt(), s = sc.nextInt(), t = sc.nextInt();
        Pair<Integer, Integer>[] cars = new Pair[n];
        for (int i = 0; i < n; i++) cars[i] = new Pair(sc.nextInt(), sc.nextInt());
        int[] g = sc.nextArrayInts(k);
        Arrays.sort(g);
        int last = 0;
        int[] distance = new int[k+1];
        for (int i = 0; i < k; i++) {
            distance[i] = g[i] - last;
            last = g[i];
        }
        distance[k]=s-last;
        int min = 0, max = 1000000001;
        while (max - min > 1) {
            int mid = (max + min) / 2;
            if (spend(mid, k+1, distance) > t) min = mid;
            else max = mid;
        }
        int ans = intINF;
        for (int i = 0; i < n; i++) {
            if (cars[i].getValue() >= max) ans = Math.min(ans, cars[i].getKey());
        }
        pw.print(ans==intINF?-1:ans);
    }

    private static int spend(int mid, int k, int[] distance) {
        int time = 0;
        for (int d : distance) {
            if (d > mid) return intINF;
            time += d + d;
            time -= Math.min(d,mid - d);
        }
        return time;
    }
}

class myScanner {
    private char[] buffer = new char[1 << 8];
    private int pos = 1;

    private BufferedReader reader;

    public myScanner(BufferedReader reader) {
        this.reader = reader;
    }

    public boolean hasNext() {
        return pos > 0;
    }

    private void loadBuffer() {
        pos = 0;
        try {
            for (int i; (i = reader.read()) != -1; ) {
                char c = (char) i;
                if (c != ' ' && c != '\n' && c != '\t' && c != '\r' && c != '\f') {
                    if (pos == buffer.length) buffer = Arrays.copyOf(buffer, 2 * pos);
                    buffer[pos++] = c;
                } else if (pos != 0) break;
            }
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    public String current() {
        return String.copyValueOf(buffer, 0, pos);
    }


    public String next() {
        loadBuffer();
        return current();
    }


    public String nextLine() {
        try {
            return reader.readLine();
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }


    public int nextInt() {
        return nextInt(10);
    }

    public long nextLong() {
        return nextLong(10);
    }

    public int nextInt(int radix) {
        loadBuffer();
        int result = 0;
        int i = buffer[0] == '-' || buffer[0] == '+' ? 1 : 0;
        for (checkValidNumber(pos > i); i < pos; i++) {
            int digit = buffer[i] - '0';
            checkValidNumber(0 <= digit && digit <= radix - 1);
            result = result * radix + digit;
        }
        return buffer[0] == '-' ? -result : result;
    }

    public long nextLong(int radix) {
        loadBuffer();
        long result = 0;
        int i = buffer[0] == '-' || buffer[0] == '+' ? 1 : 0;
        for (checkValidNumber(pos > i); i < pos; i++) {
            int digit = buffer[i] - '0';
            checkValidNumber(0 <= digit && digit <= radix - 1);
            result = result * radix + digit;
        }
        return buffer[0] == '-' ? -result : result;
    }

    public int[] nextArrayInts(int size) {
        int[] input = new int[size];
        for (int i = 0; i < size; i++) input[i] = nextInt();
        return input;
    }

    public long[] nextArrayLongs(int size) {
        long[] input = new long[size];
        for (int i = 0; i < size; i++) input[i] = nextLong();
        return input;
    }

    public double nextDouble() {
        loadBuffer();
        long result = 0;
        int i = buffer[0] == '-' || buffer[0] == '+' ? 1 : 0;
        long round = 1;
        final int radix = 10;
        boolean hasPoint = false;
        for (checkValidNumber(pos > i); i < pos; i++) {
            int digit = buffer[i] - '0';
            checkValidNumber((0 <= digit && digit <= radix - 1) || (!hasPoint && digit == -2));
            if (digit == -2) hasPoint = true;
            else {
                if (hasPoint) round *= radix;
                result = result * radix + digit;
            }

        }
        return buffer[0] == '-' ? -result / (1.0 * round) : result / (1.0 * round);
    }

    private void checkValidNumber(boolean condition) {
        if (!condition) throw new NumberFormatException(current());
    }
}