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 MAXNK = 2e5 + 10;
const long long INF = 1e18;
struct abc {
  int c, v;
};
abc a[MAXNK];
int p[MAXNK];
int n, k, s;
long long t;
long long fi = INF;
bool cmp1(abc a, abc b) { return a.v < b.v; }
bool ok(int w) {
  long long temp = 0;
  for (int i = 1; i <= k; i++) {
    int cost = (p[i] - p[i - 1]) * 2;
    if (cost <= w)
      temp += p[i] - p[i - 1];
    else {
      int ds = p[i] - p[i - 1];
      int x, y;
      if (w > ds) {
        y = w - ds;
        x = 2 * (ds - y);
        cost = y * 2 + x / 2;
        temp += (x + y);
      } else {
        if (ds == w)
          temp += 2 * ds;
        else if (w < ds)
          return false;
      }
    }
    if (temp > t) return false;
  }
  return true;
}
int main() {
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) scanf("%d%d", &a[i].c, &a[i].v);
  p[0] = 0;
  for (int i = 1; i <= k; i++) scanf("%d", &p[i]);
  sort(a + 1, a + 1 + n, cmp1);
  sort(p + 1, p + 1 + k);
  k++;
  p[k] = s;
  int l = 1, r = n, ans = -1;
  while (l <= r) {
    int m = (l + r) >> 1;
    if (ok(a[m].v)) {
      ans = m;
      r = m - 1;
    } else
      l = m + 1;
  }
  if (ans == -1) {
    puts("-1");
    return 0;
  }
  for (int i = 1; i <= n; i++) {
    if (a[i].v >= a[ans].v && a[i].c < fi) fi = a[i].c;
  }
  cout << fi << endl;
  return 0;
}
