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;
void read(vector<long long> &v) {
  for (int i = 0; i < v.size(); i++) cin >> v[i];
}
void print(vector<long long> v) {
  for (int i = 0; i < v.size(); i++) cout << v[i] << " ";
}
long long n, m, a, b, temp, x, y;
string str;
vector<long long> stations;
vector<pair<long long, long long> > cars;
long long t, k, s;
bool car(int mid) {
  long long dist = 0;
  long long time = 0;
  for (int i = 0; i < m; i++) {
    if (stations[i] - dist <= (cars[mid].first) / 2) {
      time += stations[i] - dist;
      dist = stations[i];
      continue;
    } else if (stations[i] - dist > cars[mid].first)
      return 0;
    else {
      temp = cars[mid].first;
      time += 2 * (stations[i] - dist);
      temp -= (stations[i] - dist);
      time -= temp;
      dist = stations[i];
      continue;
    }
  }
  if (time <= t) return 1;
  return 0;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n >> k >> s >> t;
  cars.resize(n);
  for (int i = 0; i < n; i++) {
    cin >> cars[i].second >> cars[i].first;
  }
  sort(cars.begin(), cars.end());
  stations.resize(k);
  read(stations);
  sort(stations.begin(), stations.end());
  stations.push_back(s);
  m = stations.size();
  int l = 0;
  int r = n - 1;
  int mid;
  while (l <= r) {
    mid = (l + r) / 2;
    if (car(mid))
      r = mid - 1;
    else
      l = mid + 1;
  }
  if (!car(n - 1)) {
    cout << -1;
    return 0;
  }
  long long mi = 1000000000000000000;
  for (int i = l; i < n; i++) {
    mi = min(mi, cars[i].second);
  }
  cout << mi;
}
