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;
const long long N = 5e5 + 100, M = 2e3 + 9, INF = 1e9 + 7, INF64 = 1e15 + 7;
pair<int, int> a[N];
int g[N];
int k, t;
struct FastIO {
  static const int S = 1310720;
  int wpos = 0;
  char wbuf[S];
  FastIO() : wpos(0) {}
  inline int xchar() {
    static char buf[S];
    static int len = 0, pos = 0;
    if (pos == len) pos = 0, len = fread(buf, 1, S, stdin);
    if (pos == len) return -1;
    return buf[pos++];
  }
  inline int xuint() {
    register int c = xchar(), x = 0;
    while (c <= 32) {
      c = xchar();
    }
    for (; '0' <= c && c <= '9'; c = xchar()) x = x * 10 + c - '0';
    return x;
  }
  inline void wchar(int x) {
    if (wpos == S) fwrite(wbuf, 1, S, stdout), wpos = 0;
    wbuf[wpos++] = x;
  }
  inline void wint(int x) {
    if (x < 0) wchar('-'), x = -x;
    char s[24];
    register int n = 0;
    while (x || !n) s[n++] = '0' + x % 10, x /= 10;
    while (n--) wchar(s[n]);
  }
  ~FastIO() {
    if (wpos) fwrite(wbuf, 1, wpos, stdout), wpos = 0;
  }
} io;
bool check(long long v) {
  register long long det, time = 0;
  for (register int i = 0; i < int(k - 1); i++) {
    det = g[i + 1] - g[i];
    if (det > v) return false;
    time += max(det, 3 * det - v);
  }
  return time <= t;
}
bool cmp(pair<int, int> a, pair<int, int> b) {
  return a.second < b.second || a.second == b.second && a.first < b.first;
}
int main() {
  int n, s, ans = INF;
  long long l, r;
  long long m;
  n = io.xuint();
  k = io.xuint();
  s = io.xuint();
  t = io.xuint();
  for (register int i = 0; i < int(n); i++) {
    a[i].first = io.xuint();
    a[i].second = io.xuint();
  }
  g[0] = 0;
  k++;
  for (register int i = 1; i < k; i++) {
    g[i] = io.xuint();
  }
  g[k++] = s;
  sort(g, g + k);
  sort(a, a + n, cmp);
  l = -1;
  r = n;
  a[n].second = INF;
  while (r - l > 1) {
    m = (l + r) / 2;
    if (check(a[m].second))
      r = m;
    else
      l = m;
  }
  if (r == n)
    io.wint(-1);
  else
    io.wint(ans);
  return 0;
}
