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;
mt19937 mrand(random_device{}());
int rnd(int x) { return mrand() % x; }
const int inf = (int)1.01e9;
const long double eps = 1e-9;
const long double pi = acos((long double)-1.0);
void precalc() {}
const int maxn = (int)2e5 + 10;
int n, k, s, t;
int cs[maxn], vs[maxn], gs[maxn];
int read() {
  if (scanf("%d%d%d%d", &n, &k, &s, &t) < 4) {
    return 0;
  }
  for (int i = 0; i < n; ++i) {
    scanf("%d%d", cs + i, vs + i);
  }
  for (int i = 0; i < k; ++i) {
    scanf("%d", gs + i);
  }
  gs[k] = s;
  return 1;
}
void solve() {
  sort(gs, gs + k);
  int left = 0, right = inf;
  while (left + 1 < right) {
    int mid = (left + right) / 2;
    int need = 0;
    int last = 0;
    for (int i = 0; i <= k; ++i) {
      int now = gs[i];
      if (now - last > mid) {
        need = inf;
        break;
      }
      int use = min((now - last) * 2, mid);
      need += now - last + ((now - last) * 2 - use);
      last = now;
    }
    if (need <= t) {
      right = mid;
    } else {
      left = mid;
    }
  }
  int res = 2 * inf;
  for (int i = 0; i < n; ++i) {
    if (vs[i] >= right) {
      res = min(res, cs[i]);
    }
  }
  if (res == 2 * inf) {
    res = -1;
  }
  printf("%d\n", res);
}
int main() {
  precalc();
  while (1) {
    if (!read()) {
      break;
    }
    solve();
  }
  return 0;
}
