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;
template <class T>
void debug(T a, T b) {
  ;
}
template <class T>
void chmin(T& a, const T& b) {
  if (a > b) a = b;
}
template <class T>
void chmax(T& a, const T& b) {
  if (a < b) a = b;
}
namespace std {
template <class S, class T>
ostream& operator<<(ostream& out, const pair<S, T>& a) {
  out << '(' << a.first << ',' << a.second << ')';
  return out;
}
}  // namespace std
long long int readL() {
  long long int res;
  scanf("%I64d", &res);
  return res;
}
void printL(long long int res) { printf("%I64d", res); }
int n, k, s, t;
pair<int, int> car[200005];
int gas[200005];
int len[200005], m;
long long int sum[200005];
int main() {
  cin >> n >> k >> s >> t;
  for (int i = 0; i < (n); ++i) scanf("%d%d", &car[i].first, &car[i].second);
  sort(car, car + n);
  for (int i = 0; i < (k); ++i) scanf("%d", &gas[i]);
  gas[k++] = 0;
  gas[k++] = s;
  sort(gas, gas + k);
  m = k - 1;
  for (int i = 0; i < (m); ++i) len[i] = gas[i + 1] - gas[i];
  sort(len, len + m);
  for (int i = 0; i < (m); ++i) sum[i + 1] += sum[i] + len[i];
  for (int i = 0; i < (n); ++i) {
    int a = car[i].second;
    ;
    ;
    if (a < len[m - 1]) continue;
    if (a % 2 == 0) {
      int lim = a / 2;
      int p = upper_bound(len, len + m, lim) - len;
      long long int time = sum[p];
      time += (sum[m] - sum[p]) * 3 - (lim * (m - p) * 2);
      ;
      ;
      ;
      ;
      if (time <= t) {
        printf("%d\n", car[i].first);
        return 0;
      }
    } else {
      int lim = a / 2;
      int p = upper_bound(len, len + m, lim) - len;
      int p2 = upper_bound(len, len + m, lim + 1) - len;
      long long int time = sum[p2] + (p2 - p);
      ;
      ;
      time += (sum[m] - sum[p2]) * 3 - ((lim * 2 + 1) * (m - p2));
      ;
      ;
      ;
      ;
      ;
      ;
      ;
      ;
      if (time <= t) {
        printf("%d\n", car[i].first);
        return 0;
      }
    }
  }
  puts("-1");
  return 0;
}
