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;
pair<int, int> car[200005];
int gas[200005];
vector<int> dist;
long long tree[200005];
constexpr int TSIZE = 200004;
void add(int p, int val) {
  for (; p <= TSIZE; p += p & -p) tree[p] += val;
}
long long query(int p) {
  long long ret = 0;
  for (; p >= 1; p -= p & -p) ret += tree[p];
  return ret;
}
int main() {
  int n, k, s, t;
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &car[i].first, &car[i].second);
  }
  for (int i = 1; i <= k; i++) {
    scanf("%d", &gas[i]);
  }
  sort(gas + 1, gas + 1 + k);
  gas[k + 1] = s;
  for (int i = 1; i <= k + 1; i++) {
    dist.push_back(gas[i] - gas[i - 1]);
  }
  sort(dist.begin(), dist.end());
  for (int i = 0; i < dist.size(); i++) {
    add(i + 1, dist[i]);
  }
  int ans = 2e9;
  for (int i = 0; i < n; i++) {
    if (dist.back() > car[i].second) continue;
    int idx =
        upper_bound(dist.begin(), dist.end(), car[i].second / 2) - dist.begin();
    long long sum1 = query(idx);
    long long sum2 = query(dist.size()) - sum1;
    if (sum1 + sum2 * 3 - car[i].second * 1ll * (dist.size() - idx) <= t)
      ans = min(ans, car[i].first);
  }
  if (ans > 1.5e9)
    printf("-1");
  else
    printf("%d", ans);
}
