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;
bool comp(pair<int, int> a, pair<int, int> b) {
  if (a.second < b.second) {
    return true;
  } else if (a.second == b.second && a.first < b.first) {
    return true;
  } else {
    return false;
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  int n, k, s;
  long long int t;
  while (cin >> n >> k >> s >> t) {
    vector<pair<int, int> > car;
    for (int i = 0; i < n; i++) {
      int c, v;
      cin >> c >> v;
      car.push_back(make_pair(c, v));
    }
    int gas[k];
    for (int i = 0; i < k; i++) {
      cin >> gas[i];
    }
    sort(car.begin(), car.end(), comp);
    sort(gas + 0, gas + k);
    int low = 0, high = n - 1;
    int mincost = -1, index;
    bool costset = false;
    bool reach = false;
    while (low <= high) {
      int mid = (high + low) / 2;
      long long int last = 0;
      long long int time = 0;
      bool unreachable = false;
      for (int i = 0; i < k; i++) {
        long long int length = gas[i] - last;
        if (length > car[mid].second) {
          unreachable = true;
          break;
        }
        if (car[mid].second / 2 >= length) {
          time += length;
        } else {
          if (car[mid].second % 2) {
            car[mid].second--;
            length--;
            time += 2;
          }
          if (car[mid].second / 2 >= length) {
            time += length;
          } else {
            time += length + (length - car[mid].second / 2) * 3;
          }
        }
        last = gas[i];
      }
      long long int length = s - last;
      if (length > car[mid].second) {
        unreachable = true;
      }
      if (car[mid].second / 2 >= length) {
        time += length;
      } else {
        if (car[mid].second % 2) {
          length--;
          time += 2;
        }
        if (car[mid].second / 2 >= length) {
          time += length;
        } else {
          time += length + (length - car[mid].second / 2) * 2;
        }
      }
      if (time <= t && !unreachable) {
        if (!costset) {
          mincost = car[mid].second;
          costset = true;
        } else {
          mincost = std::min(car[mid].second, mincost);
        }
        reach = true;
        high = mid - 1;
      } else {
        low = mid + 1;
      }
    }
    if (!reach) {
      cout << -1 << '\n';
    } else {
      int fin = -1;
      bool setfin = false;
      for (int i = 0; i < n; i++) {
        if (car[i].second < mincost) {
          continue;
        }
        if (!setfin) {
          fin = car[i].first;
          setfin = true;
        } else {
          fin = min(car[i].first, fin);
        }
      }
      std::cout << fin << '\n';
    }
  }
}
