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;
struct car {
  int c, v;
  car() = default;
  car(int c, int v) : c(c), v(v) {}
};
double getTimeMax(int v, int dist) {
  double l = 0, r = dist * 1, mid;
  for (int i = 0; i < 100; ++i) {
    mid = (l + r) / 2;
    if (mid * 2 + (dist - mid) <= v)
      l = mid;
    else
      r = mid;
  }
  return mid;
}
bool testCar(int v, const vector<int>& gas, int k, int t, int l) {
  int pos = 0, dist;
  double cont_time = 0;
  for (int i = 0; i < k + 1 && cont_time <= t; pos = gas[i], ++i) {
    if (i != k)
      dist = gas[i] - pos;
    else
      dist = l - pos;
    if (2 * dist <= v) {
      cont_time += dist;
      continue;
    }
    double time_maxv = getTimeMax(v, dist);
    double time_minv = (dist - time_maxv) * 2;
    cont_time += time_maxv + time_minv;
  }
  return cont_time <= t;
}
int main() {
  std::ios::sync_with_stdio(false);
  int n, k, l, t;
  cin >> n >> k >> l >> t;
  vector<car> cars(n);
  for (int i = 0; i < n; ++i) {
    int c, v;
    cin >> c >> v;
    cars[i] = car(c, v);
  }
  std::sort(cars.begin(), cars.end(), [](car l, car r) { return l.v <= r.v; });
  vector<int> gas(n);
  for (int i = 0; i < k; ++i) {
    cin >> gas[i];
  }
  int left = 0, right = cars.back().v, mid = 0;
  while (left < right) {
    mid = (right + left) / 2;
    if (left == mid) {
      if (!testCar(mid, gas, k, t, l)) mid++;
      break;
    }
    if (testCar(mid, gas, k, t, l)) {
      right = mid;
    } else
      left = mid + 1;
  }
  cout << lower_bound(cars.begin(), cars.end(), mid, [](car l, int r) {
            return l.v < r;
          })->c;
  return 0;
}
