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;
struct name {
  long long c, v;
} car[200010];
long long n, k, s, t, g[200010], ans;
bool cmp(name a, name b) { return a.v < b.v; }
bool cek(int x) {
  int anst = 0;
  for (int i = 1; i <= k; i++) {
    int a = g[i] - g[i - 1];
    if (car[x].v >= a) {
      anst += 2 * a;
      if (car[x].v >= 2 * a) {
        anst -= a;
      } else {
        anst -= (car[x].v - a);
      }
    } else
      return false;
  }
  int a = s - g[k];
  if (car[x].v >= a) {
    anst += 2 * a;
    if (car[x].v >= 2 * a) {
      anst -= a;
    } else {
      anst -= (car[x].v - a);
    }
  } else
    return false;
  if (anst <= t) {
    return true;
  } else
    return false;
}
void binser() {
  int lo = 1, hi = n, mid;
  while (lo <= hi) {
    mid = (lo + hi) / 2;
    if (cek(mid)) {
      ans = mid;
      hi = mid - 1;
    } else {
      lo = mid + 1;
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ans = -1;
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) {
    cin >> car[i].c >> car[i].v;
  }
  for (int i = 1; i <= k + 1; i++) {
    cin >> g[i];
  }
  ans = -1;
  sort(g + 1, g + k + 1);
  sort(car + 1, car + n + 1, cmp);
  binser();
  if (ans == -1) {
    cout << ans << endl;
    return 0;
  }
  long long mins = 2e9;
  for (int i = ans; i <= n; i++) {
    mins = min(mins, car[i].c);
  }
  cout << mins << endl;
  return 0;
}
