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 TCar {
  int c, v;
};
struct TVolComp {
  bool operator()(const TCar &a, const TCar &b) { return a.v < b.v; }
};
struct TPriceComp {
  bool operator()(const TCar &a, const TCar &b) { return a.c < b.c; }
};
bool check(const vector<int> &gas, int v, int s, int t) {
  if (gas[0] > v) {
    return false;
  }
  int res = max(0, 2 * gas[0] - v) + gas[0];
  for (int i = 1; i <= gas.size() - 1; ++i) {
    int l = gas[i] - gas[i - 1];
    if (l > v) {
      return false;
    }
    res += max(0, 2 * l - v) + l;
  }
  int l = s - gas.back();
  if (l > v) {
    return false;
  }
  res += max(0, 2 * l - v) + l;
  return res <= t;
}
int main() {
  ios_base::sync_with_stdio(false);
  int n, k, s, t;
  cin >> n >> k >> s >> t;
  vector<TCar> car(n);
  for (auto &x : car) {
    cin >> x.c >> x.v;
  }
  sort(car.begin(), car.end(), TVolComp());
  vector<int> gas(k);
  for (int &x : gas) {
    cin >> x;
  }
  sort(gas.begin(), gas.end());
  if (!check(gas, car.back().v, s, t)) {
    cout << -1;
    return 0;
  }
  int l = 0, r = n - 1;
  while (l < r) {
    int m = (l + r) / 2;
    if (check(gas, car[m].v, s, t)) {
      r = m;
    } else {
      l = m + 1;
    }
  }
  int v = car[l].v;
  sort(car.begin(), car.end(), TPriceComp());
  cout << find_if(car.begin(), car.end(), [v](const TCar &x) -> bool {
            return x.v >= v;
          })->c;
  return 0;
}
