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 = 200010;
struct Car {
  int c, v;
} car[maxn];
int n, k, s, t;
int g[maxn];
bool cmp(Car a, Car b) { return a.v != b.v ? a.v < b.v : a.c < b.c; }
bool ok(int x) {
  int loc = 0;
  long long now = 0;
  for (int i = 0; i < k; i++) {
    int dis = g[i] - loc;
    if (dis > x) return false;
    now += max(2 * dis - x, 0) + dis;
    if (now >= t) return false;
    loc = g[i];
  }
  int dis = s - loc;
  if (dis > x) return false;
  now += max(2 * dis - x, 0) + dis;
  return now <= t;
}
int main() {
  scanf("%d%d%d%d", &n, &k, &s, &t);
  if (t < s) {
    printf("-1");
    return 0;
  }
  for (int i = 0; i < n; i++) scanf("%d%d", &car[i].c, &car[i].v);
  sort(car, car + n, cmp);
  for (int i = 0; i < k; i++) scanf("%d", &g[i]);
  sort(g, g + k);
  int lo = car[0].v, hi = car[n - 1].v;
  if (!ok(hi)) {
    printf("-1");
    return 0;
  }
  while (lo < hi) {
    int mid = (lo + hi) / 2;
    if (ok(mid))
      hi = mid;
    else
      lo = mid + 1;
  }
  int ans = lo;
  lo = 0;
  hi = n - 1;
  while (lo < hi) {
    int mid = (lo + hi) / 2;
    if (car[mid].v >= ans)
      hi = mid;
    else
      lo = mid + 1;
  }
  printf("%d", car[lo].c);
  return 0;
}
