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 gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
const int MAXQ = 200000;
const int MAXN = 200000;
typedef struct Q {
  int p, cap;
} Q;
bool operator<(const Q &a, const Q &b) {
  if (a.p != b.p) return a.p < b.p;
  return a.cap >= b.cap;
}
int nq, n, s, t;
Q q[MAXQ];
int x[MAXN];
bool ok(int cap) {
  int left = t;
  for (int i = (0); i <= (n); ++i) {
    long long d = (i == n ? s : x[i]) - (i == 0 ? 0 : x[i - 1]);
    if (d > cap) return false;
    long long need = 2 * d <= cap ? d : 3 * d - cap;
    if (need > left)
      return false;
    else
      left -= need;
  }
  return true;
}
void run() {
  scanf("%d%d%d%d", &nq, &n, &s, &t);
  for (int i = (0); i < (nq); ++i) scanf("%d%d", &q[i].p, &q[i].cap);
  for (int i = (0); i < (n); ++i) scanf("%d", &x[i]);
  sort(x, x + n);
  {
    sort(q, q + nq);
    int m = 0;
    for (int i = (0); i < (nq); ++i)
      if (m == 0 || q[i].cap > q[m - 1].cap) q[m++] = q[i];
    nq = m;
  }
  int l = -1, h = nq;
  while (l + 1 < h) {
    int m = l + (h - l) / 2;
    if (ok(q[m].cap))
      h = m;
    else
      l = m;
  }
  printf("%d\n", h == nq ? -1 : q[h].p);
}
int main() {
  run();
  return 0;
}
