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;
int c[200010], v[200010], g[200010];
int main() {
  int n, k, s, t;
  while (scanf("%d%d%d%d", &n, &k, &s, &t) > 0) {
    for (int i = 0; i < n; i++) {
      scanf("%d%d", &c[i], &v[i]);
    }
    g[0] = 0;
    for (int i = 1; i <= k; i++) {
      scanf("%d", &g[i]);
    }
    g[k + 1] = s;
    sort(g, g + k + 2);
    int ans = (1 << 30);
    for (int i = 0; i < n; i++) {
      long long acum = 0;
      for (int j = 1; j <= k + 1; j++) {
        int L = g[j] - g[j - 1];
        if (L > v[i]) {
          acum = t + 1;
          break;
        }
        acum += 2 * L - min(L, v[i] - L);
      }
      if (acum <= t and (ans == -1 or c[i] < ans)) {
        ans = c[i];
      }
    }
    printf("%d\n", ans);
  }
}
