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>
#pragma comment(linker, "/STACK:20000000")
using namespace std;
long long minl(long long a, long long b) {
  if (a < b)
    return a;
  else
    return b;
}
struct car {
  long long c, v;
};
int main() {
  long long n, k, s, t;
  cin >> n >> k >> s >> t;
  vector<car> A;
  vector<long long> zapr;
  A.resize(n);
  zapr.resize(k);
  for (int i = 0; i < n; i++) cin >> A[i].c >> A[i].v;
  for (int i = 0; i < k; i++) cin >> zapr[i];
  k += 2;
  zapr.push_back(0);
  zapr.push_back(s);
  sort(zapr.begin(), zapr.end());
  long long l = 1, r = 10e11;
  while (l != r) {
    long long m = (l + r) / 2;
    long long timeloc = 0;
    for (int i = 0; i < k - 1; i++) {
      long long dist = zapr[i + 1] - zapr[i];
      long long x = minl(m - dist, dist);
      timeloc = timeloc + x + (dist - x) * 2;
      if (x == -1) timeloc += t + 1;
    }
    if (timeloc <= t) {
      r = m;
    } else {
      l = m + 1;
    }
  }
  long long low = 10e11;
  for (int i = 0; i < n; i++) {
    if (A[i].v >= l) {
      low = minl(low, A[i].c);
    }
  }
  cout << low;
  return 0;
}
