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:5000000000")
const long long mod = 1000000007;
int Inf = (int)2e9;
using namespace std;
long long n, k, s, t;
bool yes = 0;
vector<pair<long long, long long>> cars;
vector<long long> zap;
long long T = 0;
bool can(long long idx) {
  T = 0;
  for (int i = 1; i < zap.size(); i++) {
    long long x = zap[i] - zap[i - 1];
    if (x > idx) return false;
    long long mx = idx - x;
    T += min(mx, x) + max(0ll, x - mx) * 2;
  }
  return 1;
}
int main() {
  cin >> n >> k >> s >> t;
  cars.resize(n);
  for (int(i) = 0; (i) < n; (i)++) {
    scanf("%I64d", &(cars[i].second));
    scanf("%I64d", &(cars[i].first));
  }
  sort((cars).begin(), (cars).end());
  zap.resize(k);
  zap.push_back(0);
  zap.push_back(s);
  for (int(i) = 0; (i) < k; (i)++) scanf("%I64d", &(zap[i]));
  if (t > 2 * s) {
    puts("-1");
    return 0;
  }
  sort((zap).begin(), (zap).end());
  long long l = 1, r = 2e9 + 5;
  while (r - l > 1) {
    long long m = (r + l) / 2;
    if (can(m)) {
      if (T <= t)
        r = m;
      else
        l = m;
    } else
      l = m;
  }
  if (l > s) {
    puts("-1");
    return 0;
  }
  long long ans = 1e18;
  for (int(i) = 0; (i) < n; (i)++) {
    if (cars[i].first >= r) {
      ans = min(ans, cars[i].second);
    }
  }
  if (ans == 1e18) ans = -1;
  cout << ans;
  return 0;
}
