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;
int n, t, s, m, g[20005], mx, dis[20005];
struct car {
  int c, v;
} d[10005];
bool cmp(car a, car b) { return a.c < b.c || a.c < b.c && a.v == b.v; }
bool check(car x) {
  int tim = 0;
  for (int i = 0; i <= m; i++) {
    if (x.v < dis[i]) {
      return false;
    }
    if (x.v >= dis[i] * 2)
      tim += dis[i];
    else {
      int k = x.v - dis[i];
      tim += dis[i] * 2 - k;
    }
    if (tim > t) return false;
  }
  return tim <= t;
}
int main() {
  cin >> n >> m >> s >> t;
  for (int i = 0; i < n; i++) {
    cin >> d[i].c >> d[i].v;
  }
  for (int i = 0; i < m; i++) cin >> g[i];
  sort(g, g + m);
  dis[0] = g[0];
  for (int i = 0; i < m - 1; i++) {
    mx = max(g[i + 1] - g[i], mx);
    dis[i + 1] = g[i + 1] - g[i];
  }
  dis[m] = s - g[m - 1];
  sort(d, d + n, cmp);
  for (int i = 0; i < n; i++) {
    if (check(d[i])) {
      cout << d[i].c << '\n';
      return 0;
    }
  }
  int l = 0, r = n - 1;
  return 0;
}
