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;
const bool print = false;
const int MAXN = 200111;
int n, k, s, t;
vector<pair<int, int> > cars;
vector<int> stations;
int chk(int tank) {
  int pop = 0;
  int ans = 0;
  for (auto it : stations) {
    int odl = it - pop;
    int time = 2 * odl;
    int left = tank - odl;
    if (left < 0) return t + 69;
    time -= left;
    if (time < odl) time = odl;
    ans += time;
    pop = it;
  }
  return ans;
}
int main() {
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = (1); i <= (n); i++) {
    int c, v;
    scanf("%d%d", &c, &v);
    cars.emplace_back(c, v);
  }
  for (int i = (1); i <= (k); i++) {
    int a;
    scanf("%d", &a);
    stations.push_back(a);
  }
  stations.push_back(s);
  sort((cars).begin(), (cars).end());
  sort((stations).begin(), (stations).end());
  int pop = 0;
  for (auto& it : cars) {
    if (pop > it.second) it.second = pop;
    pop = it.second;
  }
  int lw = 1, pw = n;
  while (lw < pw) {
    int sr = (lw + pw) / 2;
    int time69 = chk(cars[sr - 1].first);
    if (time69 <= t)
      pw = sr;
    else
      lw = sr + 1;
  }
  printf("%d\n", cars[lw - 1].first);
}
