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;
int n, k, i;
long long s, t, x;
pair<long long, long long> cars[200011];
vector<long long> gas;
long long ans, solution;
long long check(long long vol) {
  long long ans = 0;
  for (int i = 1; i < gas.size(); i++) {
    long long dim = gas[i] - gas[i - 1];
    ans += 2 * dim - min(dim, vol - dim);
  }
  return ans;
}
int main() {
  scanf("%d%d%lld%lld", &n, &k, &s, &t);
  for (i = 1; i <= n; i++) scanf("%lld%lld", &cars[i].first, &cars[i].second);
  gas = {0, s};
  for (i = 1; i <= k; i++) {
    scanf("%lld", &x);
    gas.push_back(x);
  }
  sort(gas.begin(), gas.end());
  gas.resize(unique(gas.begin(), gas.end()) - gas.begin());
  for (i = 1; i < gas.size(); i++) ans = max(ans, gas[i] - gas[i - 1] - 1);
  for (long long step = (1LL << 33); step > 0; step >>= 1) {
    if (check(ans + step) > t) ans += step;
  }
  ans++;
  solution = 1LL << 60;
  for (i = 1; i <= n; i++) {
    if (cars[i].second < ans) continue;
    solution = min(solution, cars[i].first);
  }
  if (solution == 1LL << 60) {
    printf("-1");
    return 0;
  }
  printf("%lld", solution);
  return 0;
}
