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 main() {
  vector<int> p, l;
  scanf("%d %d %d %d", &N, &K, &S, &T);
  vector<pair<int, int> > car;
  for (int i = 0; i < N; i++) {
    int c, g;
    scanf("%d %d", &c, &g);
    car.push_back({g, c});
  }
  sort(car.begin(), car.end());
  for (int i = 0; i < K; i++) {
    int x;
    scanf("%d", &x);
    p.push_back(x);
  }
  p.push_back(0);
  p.push_back(S);
  sort(p.begin(), p.end());
  for (int i = 1; i < p.size(); i++) l.push_back(p[i] - p[i - 1]);
  sort(l.begin(), l.end());
  long long sum = 0;
  int i = 0;
  long long fullt = 0, subc = 0, subt = 0;
  for (int x : l) {
    subc++;
    subt += x * 3ll;
  }
  int ans = 0x7fffffff;
  for (auto p : car) {
    if (p.first < l.back()) continue;
    while (i < l.size() && l[i] * 2 < p.first) {
      subc--;
      subt -= l[i] * 3ll;
      fullt += l[i];
      i++;
    }
    long long now = subt - subc * p.first + fullt;
    if (now <= T) {
      if (ans > p.second) ans = p.second;
    }
  }
  if (ans == 0x7fffffff) ans = -1;
  printf("%d\n", ans);
  return 0;
}
