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 = 200500;
const int inf = 1e9;
const double eps = 1e-8;
const int base = 1073676287;
pair<int, int> a[maxn];
int pos[maxn];
bool correct(int g, int k, int S, int t) {
  int curPos = 0;
  int sumTime = 0;
  for (int j = 0; j < k; j++) {
    if (g < pos[j] - curPos) return false;
    if (g >= 2 * (pos[j] - curPos)) {
      sumTime += pos[j] - curPos;
      curPos = pos[j];
      continue;
    }
    int delta = pos[j] - curPos;
    int x = g - delta;
    sumTime += x + 2 * (delta - x);
    curPos = pos[j];
  }
  return sumTime <= t;
}
int main() {
  srand(time(0));
  int n, k, S, t;
  scanf("%d%d%d%d", &n, &k, &S, &t);
  for (int j = 0; j < n; j++) scanf("%d%d", &a[j].first, &a[j].second);
  for (int j = 0; j < k; j++) scanf("%d", &pos[j]);
  pos[k] = S;
  ++k;
  sort(pos, pos + k);
  int l = 1, r = inf + 1;
  while (r - l) {
    int mid = (l + r) >> 1;
    if (!correct(mid, k, S, t))
      l = mid + 1;
    else
      r = mid;
  }
  int ans = inf;
  for (int j = 0; j < n; j++)
    if (a[j].second >= l) ans = min(ans, a[j].first);
  if (ans == inf)
    puts("-1");
  else
    printf("%d\n", ans);
  return 0;
}
