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>
template <typename T>
bool _max(T& a, T b) {
  return (a < b) ? a = b, true : false;
}
template <typename T>
bool _min(T& a, T b) {
  return (b < a) ? a = b, true : false;
}
unsigned S[200005];
std::pair<unsigned, unsigned> P[200005];
int main() {
  unsigned n, k, s, l = 0, ans = -1;
  unsigned long long t, wil, lazy = 0;
  scanf("%u%u%u%llu", &n, &k, &s, &t), S[0] = 0, S[k + 1] = s;
  for (unsigned i = 0; i < n; i++) scanf("%u%u", &P[i].second, &P[i].first);
  std::sort(P, P + n);
  for (unsigned i = 1; i <= k; i++) scanf("%u", S + i);
  std::sort(S + 1, S + k + 1);
  for (unsigned i = 0; i <= k; i++) S[i] = S[i + 1] - S[i];
  std::sort(S, S + k + 1);
  for (unsigned i = 0; i < n; i++) {
    if (S[k] > P[i].first || P[i].second >= ans) continue;
    while (l <= k && P[i].first >= 2 * S[l]) lazy += S[l++];
    wil = lazy;
    for (unsigned j = l; j <= k; j++) wil += 3 * S[j] - P[i].first;
    if (wil <= t) _min(ans, P[i].second);
  }
  printf("%d\n", (~ans) ? (int)ans : -1);
  return 0;
}
