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

#include <bits/stdc++.h>
using namespace std;
struct car {
  int m, v;
} a[200005];
int nu[200005];
bool cmp(car a1, car a2) { return a1.m < a2.m; }
int main() {
  int n, k, s, t;
  while (cin >> n >> k >> s >> t) {
    for (int i = 0; i < n; i++) {
      cin >> a[i].m >> a[i].v;
    }
    sort(a, a + n, cmp);
    int p, q;
    int ma[200005];
    for (int i = 0; i < k; i++) {
      cin >> ma[i];
    }
    sort(ma, ma + k);
    nu[0] = ma[0];
    for (int i = 1; i < k; i++) {
      nu[i] = ma[i] - ma[i - 1];
    }
    nu[k] = s - ma[k - 1];
    k++;
    for (int i = 0; i < n; i++) {
      int f = 0;
      int t1 = t;
      for (int j = 0; j < k; j++) {
        if ((nu[j] > a[i].v)) {
          f = 1;
        } else if (nu[j] < (a[i].v) / 2) {
          t1 = t1 - nu[j];
        } else {
          t1 = t1 - (3 * nu[j] - a[i].v);
        }
        if (f == 1) {
          t1 = -100;
          break;
        }
      }
      if (t1 >= 0) {
        cout << a[i].m << endl;
        break;
      }
    }
  }
}
