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;
vector<pair<int, int> > a;
vector<int> g;
bool ok(int v) {
  int time = 0;
  for (int i = 1; i < g.size(); i++) {
    int d = g[i] - g[i - 1];
    int x = v - d;
    if (x < 0) return 0;
    if (x > d)
      time += d;
    else
      time += x + 2 * (d - x);
  }
  return (time <= t);
}
int main() {
  cin >> n >> k >> s >> t;
  g.resize(k);
  a.resize(n);
  g.push_back(0);
  g.push_back(s);
  for (int i = 0; i < n; i++) cin >> a[i].second >> a[i].first;
  for (int i = 0; i < k; i++) cin >> g[i];
  sort(a.begin(), a.end());
  sort(g.begin(), g.end());
  int l = 0, r = n - 1, ans = 0;
  while (l <= r) {
    int mid = (l + r) / 2;
    if (!ok(a[mid].first))
      l = mid + 1;
    else {
      ans = mid;
      r = mid - 1;
    }
  }
  int res = 1e9;
  for (int i = ans; i < n; i++) res = min(res, a[i].second);
  cout << res;
}
