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.util.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int k = in.nextInt();
        int s = in.nextInt();
        int t = in.nextInt();

        int[] ci = new int[n];
        int[] vi = new int[n];

        for (int i = 0; i < n; i++) {
            ci[i] = in.nextInt();
            vi[i] = in.nextInt();
        }

        int g[] = new int[k];

        for (int i = 0; i < k; i++) {
            g[i] = in.nextInt();
        }
        Arrays.sort(g);
        int distance[] = new int[k + 1];
        distance[0] = g[0];
        int maxDistance = 0;
        for (int i = 1; i < k; i++) {
            distance[i] = g[i] - g[i - 1];
            maxDistance = Math.max(distance[i], maxDistance);
        }
        distance[k] = s - g[k - 1];
        maxDistance = Math.max(distance[k], maxDistance);

        int cmin = -1;

        for (int i = 0; i < n; i++) {
            if (vi[i] >= maxDistance && (cmin == -1 || cmin > ci[i])) {
                int time = 0;
                for (int j = 0; j < k + 1; j++)
                    time += Math.min(2 * distance[i], 3 * distance[i] - vi[i]);
                if (time <= t)
                    cmin = ci[i];
            }
        }
        System.out.println(cmin);

    }
}
