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, k, s, t, c[200005], v[200005], q[200005], g[200005], d[200005], ans;
bool cmp(int x, int y) { return x < y; }
bool ok(int x) {
  long long tot = 0;
  for (int i = (0); i < (k + 1); i++) {
    if (d[i] + d[i] <= x)
      tot += d[i];
    else if (d[i] <= x)
      tot += 3LL * d[i] - x;
    else
      return 0;
  }
  return tot <= t;
}
int main() {
  scanf("%d %d %d %d", &n, &k, &s, &t);
  for (int i = (0); i < (n); i++) scanf("%d %d", &c[i], &v[i]);
  g[0] = 0;
  for (int i = (1); i <= (k); i++) scanf("%d", &g[i]);
  g[k + 1] = s;
  sort(g, g + k + 2);
  for (int i = (0); i < (k + 1); i++) d[i] = g[i + 1] - g[i];
  int l = 0, h = 1000000001;
  while (l < h) {
    int m = (long long)l + h >> 1;
    if (ok(m))
      h = m;
    else
      l = m + 1;
  }
  ans = 2e9;
  for (int i = (0); i < (n); i++)
    if (c[i] < ans && v[i] >= h) ans = c[i];
  printf("%d\n", ans > 1.5e9 ? -1 : ans);
}
