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 MN = 2e5 + 7;
long long v[MN], c[MN], g[MN], n, k, s, t;
bool ok(int x) {
  int sw = 0;
  int now = 0, re = 0;
  for (int i = 0; i < k + 1; i++) {
    if (x < g[i] - now) {
      return false;
    }
    if (x == g[i] - now) {
      re += (g[i] - now) * 2;
      if (re > t) return false;
      continue;
    }
    if ((g[i] - now) % 2) {
      if (sw) {
        sw = 0;
        now--;
      } else {
        now++;
        re += 2;
        sw = 1;
      }
    }
    re += (g[i] - now) * 2 - (min(g[i] - now, x - (g[i] - now)));
    now = g[i];
    if (re > t) return false;
  }
  if (re > t) {
    return false;
  }
  return true;
}
int main() {
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) {
    cin >> c[i] >> v[i];
  }
  for (int i = 0; i < k; i++) {
    cin >> g[i];
  }
  g[k] = s;
  sort(g, g + k + 1);
  long long mini = 0, maxi = s;
  while (maxi - mini > 1) {
    long long mid = (mini + maxi) / 2;
    if (ok(mid)) {
      maxi = mid;
    } else {
      mini = mid;
    }
  }
  long long ans = 2e9 + 7;
  for (int i = 0; i < n; i++) {
    if (v[i] >= maxi) {
      ans = min(ans, c[i]);
    }
  }
  cout << ans;
}
