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;
long long n, m, ln, ti, a[200069], cp[200069], pst[200069], dis[200069],
    ps[200069];
int main() {
  long long i, p, sm, z = 1e18;
  scanf("%lld%lld%lld%lld", &n, &m, &ln, &ti);
  for (i = 1; i <= n; i++) {
    scanf("%lld%lld", a + i, cp + i);
  }
  for (i = 1; i <= m; i++) {
    scanf("%lld", pst + i);
  }
  sort(pst + 1, pst + m + 1);
  m++;
  pst[m] = ln;
  for (i = 1; i <= m; i++) {
    dis[i] = pst[i] - pst[i - 1];
  }
  sort(dis + 1, dis + m + 1);
  for (i = 1; i <= m; i++) {
    ps[i] = ps[i - 1] + dis[i];
  }
  for (i = 1; i <= n; i++) {
    if (cp[i] >= dis[m]) {
      p = upper_bound(dis + 1, dis + m + 1, cp[i] / 2) - dis - 1;
      sm = ps[p] + (ps[m] - ps[p]) * 3 - cp[i] * (m - p);
      if (sm <= ti) {
        z = min(z, a[i]);
      }
    }
  }
  if (z == 1000000000000000000) {
    z = -1;
  }
  cout << z;
  return 0;
}
