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, s, t, c[200005], v[200005], g[200005], minv, minc = -1;
long long f(long long x, long long y) {
  if (y >= x * 2) return x;
  return 3 * x - y;
}
long long time_use(int x) {
  long long tu = 0;
  if (g[0] > x) return 2e9 + 1;
  tu += f(g[0], x);
  for (int i = 1; i < k; i++) {
    if (g[i] - g[i - 1] > x) return 2e9 + 1;
    tu += f(g[i] - g[i - 1], x);
  }
  if (s - g[k - 1] > x) return 2e9 + 1;
  tu += f(s - g[k - 1], x);
  return tu;
}
int main() {
  scanf("%d %d %d %d", &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", &g[i]);
  sort(g, g + k);
  for (long long l = 1, r = 2e9;;) {
    if (l == r) {
      minv = l;
      break;
    }
    long long mid = (l + r) / 2;
    if (time_use(mid) <= t)
      r = mid;
    else
      l = mid + 1;
  }
  for (int i = 0; i < n; i++)
    if (v[i] >= minv && (minc == -1 || c[i] < minc)) minc = c[i];
  printf("%d\n", minc);
}
