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;
const int maxn = 201010;
struct Car {
  int c, v;
} b[maxn];
int x[maxn], a[maxn];
int k;
inline long long get(int lim) {
  long long ans = 0;
  for (int i = 1; i <= k; i++) {
    if (a[i] > lim)
      return 0;
    else if (a[i] * 2 <= lim)
      ans += a[i];
    else
      ans += lim - a[i];
  }
  return ans;
}
int main() {
  int n, t, s;
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) scanf("%d%d", &b[i].c, &b[i].v);
  int prev = 0;
  for (int i = 1; i <= k; i++) scanf("%d", &x[i]);
  sort(x + 1, x + k + 1);
  for (int i = 1; i <= k; i++) a[i] = x[i] - x[i - 1];
  a[k + 1] = s - x[k];
  k++;
  long long sum = 0;
  sort(a + 1, a + k + 1);
  for (int i = 1; i <= k; i++) sum += a[k] - a[i];
  if (t < s) {
    cout << "-1";
    return 0;
  }
  int cnt = max(0, 2 * s - t);
  long long l = a[k], r = 2 * s, mid;
  while (r - l > 1) {
    mid = (l + r) / 2;
    if (get(mid) >= cnt)
      r = mid;
    else
      l = mid;
  }
  int cap;
  if (get(l) >= cnt)
    cap = l;
  else
    cap = r;
  int id = -1;
  for (int i = 1; i <= n; i++) {
    if (b[i].v >= cap) {
      if (id == -1 || b[i].c < b[id].c) id = i;
    }
  }
  if (id == -1) {
    cout << "-1";
    return 0;
  }
  cout << b[id].c;
  return 0;
}
