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;
static int x = []() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  return 0;
}();
long long int min(long long int a, long long int b) {
  if (a == -1) return b;
  if (b == -1) return a;
  if (a > b) return b;
  return a;
}
int main() {
  long long int n, k, s, t;
  cin >> n >> k >> s >> t;
  long long int gass[k];
  long long int arr[n], brr[n];
  for (long long int i = 0; i < n; i++) {
    cin >> arr[i] >> brr[i];
  }
  for (long long int i = 0; i < k; i++) cin >> gass[i];
  sort(gass, gass + k);
  long long int mindis = 0;
  long long int cap = 0;
  for (auto i : gass) {
    mindis = max(mindis, i - cap);
    cap = i;
  }
  mindis = max(mindis, s - cap);
  cap = 0;
  long long int mincap = 0;
  for (auto i : gass) {
    mincap = max(mincap, 2 * (i - cap));
    cap = i;
  }
  mincap = max(mincap, 2 * (s - cap));
  long long int lef = mindis, rig = mincap;
  while (lef <= rig) {
    long long int fuel = rig + (lef - rig) / 2;
    long long int count = 0;
    long long int bac = 0;
    long long int dis = 0;
    for (long long int i = 0; i < k; i++) {
      long long int dis = gass[i] - bac;
      if (fuel >= 2 * dis) {
        if (dis != 0) count += dis;
      } else if (fuel - dis < 0) {
        lef = fuel + 1;
        goto en;
      } else if (dis != 0) {
        count += 3 * dis - fuel;
      }
      bac = gass[i];
    }
    dis = s - bac;
    if (fuel >= 2 * dis) {
      if (dis != 0) count += dis;
    } else if (fuel - dis < 0) {
      lef = fuel + 1;
      continue;
    } else if (dis != 0) {
      count += 3 * dis - fuel;
    }
    if (count <= t) {
      mincap = min(mincap, fuel);
      rig = fuel - 1;
    } else {
      lef = fuel + 1;
    }
  en:;
  }
  long long int ans = -1;
  for (long long int i = 0; i < n; i++) {
    if (brr[i] >= mincap) {
      ans = min(ans, arr[i]);
    }
  }
  cout << ans << endl;
}
