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 int N = 200005;
const long long oo = 1000000000000LL;
long long g[N], c[N], v[N], n, k, s, t;
bool check(long long M) {
  long long T = t;
  for (int i = 1; i < k; ++i) {
    long long len = g[i + 1] - g[i];
    long long x = max(0LL, len * 2 - M);
    long long y = len - x;
    if (y < 0 || T < x * 2 + y || x + 2 * y > M) return false;
    T -= x * 2 + y;
  }
  return T >= 0;
}
long long solve() {
  long long L = 0, R = s * 5, res = oo;
  while (L <= R) {
    long long M = (L + R) >> 1;
    if (check(M)) {
      res = M;
      R = M - 1;
    } else
      L = M + 1;
  }
  return res;
}
int main() {
  scanf("%I64d%I64d%I64d%I64d", &n, &k, &s, &t);
  for (int i = 1; i <= n; ++i) scanf("%I64d%I64d", &c[i], &v[i]);
  for (int i = 1; i <= k; ++i) scanf("%I64d", &g[i]);
  g[++k] = 0;
  g[++k] = s;
  sort(g + 1, g + k + 1);
  long long G = solve();
  long long res = oo;
  for (int i = 1; i <= n; ++i)
    if (v[i] >= G) res = min(res, c[i]);
  if (res == oo)
    cout << -1 << endl;
  else
    cout << res << endl;
  return 0;
}
