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 maxn = 2e5 + 20;
pair<long long, long long> p[maxn];
long long A[maxn], B[maxn];
long long n, k, s, t;
long long cal(long long x) {
  long long time = 0;
  for (int i = 1; i <= k + 1; i++) {
    if (2 * (A[i] - A[i - 1]) <= x) {
      time += A[i] - A[i - 1];
    } else if (A[i] - A[i - 1] <= x)
      time += 3 * (A[i] - A[i - 1]) - x;
    else
      return 3e18;
  }
  return time;
}
int main(void) {
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) scanf("%lld%lld", &p[i].second, &p[i].first);
  A[0] = 0;
  A[k + 1] = s;
  for (int i = 1; i <= k; i++) scanf("%lld", &A[i]);
  sort(p, p + n);
  sort(A + 1, A + k + 1);
  if (cal(p[n - 1].first) > t)
    cout << -1;
  else {
    int L = 0, R = n - 1, mid;
    while (R - L > 3) {
      mid = L + (R - L + 1) / 2;
      if (cal(mid) > t)
        L = mid - 1;
      else
        R = mid;
    }
    int x;
    for (int i = L; i <= R; i++) {
      if (cal(p[i].first) <= t) {
        x = i;
        break;
      }
    }
    long long res = 3e18;
    for (int i = x; i < n; i++) {
      res = min(res, p[i].second);
    }
    cout << res << endl;
  }
}
