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;
const int maxC = 1000000001;
const int maxNode = 10230997;
const int maxN = 1000006;
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, -1, 0, 1};
const double epsilon = 1e-9;
int n, k, t, res;
pair<int, int> car[maxN];
int a[maxN];
void NhapDL() {
  int s;
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = 0; i < n; ++i) scanf("%d%d", &car[i].first, &car[i].second);
  for (int i = 1; i < k + 1; ++i) scanf("%d", &a[i]);
  a[0] = 0;
  a[k + 1] = s;
  k++;
}
bool check(int val) {
  long long time = 0;
  for (int i = 1; i < k + 1; ++i) {
    int d = a[i] - a[i - 1];
    if (d > val) return false;
    if (2 * d < val)
      time += val;
    else
      time += (long long)3 * d - val;
  }
  return time <= t;
}
void solve() {
  int m;
  int l = 0, r = 1e9;
  while (r - l > 1) {
    int m = l + ((r - l) >> 1);
    if (check(m))
      r = m;
    else
      l = m;
  }
  res = maxC;
  for (int i = 0; i < n; ++i)
    if (car[i].second >= m) res = min(res, car[i].first);
  if (res == maxC) res = -1;
}
int main() {
  NhapDL();
  solve();
  printf("%d", res);
  return 0;
}
