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:60777216")
using namespace std;
int n, k, s, t;
int c[222222];
int v[222222];
int x[222222];
bool good(long long V) {
  long long tt = 0;
  for (int i = (1); i < (k); i++) {
    int d = x[i] - x[i - 1];
    if (d > V) return 0;
    int diff = V - d;
    tt += 2 * d;
    tt -= min(d, diff);
  }
  return tt <= t;
}
int main() {
  cin >> n >> k >> s >> t;
  for (int i = (0); i < (n); i++) scanf("%d %d", c + i, v + i);
  for (int i = (0); i < (k); i++) scanf("%d", x + i + 1);
  k++;
  x[k] = s;
  k++;
  sort(x, x + k);
  long long best = -1;
  long long from = 0, to = s;
  while (from <= to) {
    long long m = (from + to) / 2;
    if (good(m))
      best = m, to = m - 1;
    else
      from = m + 1;
  }
  if (best == -1) {
    puts("-1");
    return 0;
  }
  int res = 2e9;
  for (int i = (0); i < (n); i++)
    if (v[i] >= best) res = min(res, c[i]);
  if (res == 2e9)
    puts("-1");
  else
    cout << res << endl;
  return 0;
}
