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 n, k, s, T;
int maxdis;
int g[500010];
struct dian {
  int c;
  int v;
} node[500010];
int func(int sum) {
  int t = 0;
  for (int i = 1; i < k; i++) {
    int dis = g[i] - g[i - 1];
    if (sum >= 2 * dis)
      t += dis;
    else
      t += 3 * dis - sum;
  }
  return t;
}
int erfen(int t) {
  int l = 1;
  int r = 2000000000;
  while (l != r) {
    int mid = (l + r) / 2;
    if (func(mid) == t)
      return mid;
    else if (func(mid) < t)
      r = mid;
    else
      l = mid + 1;
  }
  return l;
}
int cmp(dian a, dian b) { return a.c < b.c; }
bool judge(int x) {
  if (node[x].v < maxdis) return false;
  if (func(node[x].v) > T) return false;
  return true;
}
int main() {
  while (~scanf("%d %d %d %d", &n, &k, &s, &T)) {
    for (int i = 0; i < n; i++) {
      scanf("%d %d", &node[i].c, &node[i].v);
    }
    for (int i = 0; i < k; i++) {
      scanf("%d", &g[i]);
    }
    g[k++] = 0;
    g[k++] = s;
    sort(g, g + k);
    maxdis = 0;
    for (int i = 1; i < k; i++) {
      maxdis = max(maxdis, g[i] - g[i - 1]);
    }
    int ans = erfen(T);
    sort(node, node + n, cmp);
    int flag = 0;
    for (int i = 0; i < n; i++) {
      if (judge(i)) {
        if (node[i].v >= ans) {
          printf("%d\n", node[i].c);
          flag = 1;
          break;
        }
      }
    }
    if (!flag) {
      printf("-1\n");
    }
  }
  return 0;
}
