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>
struct car {
  int c, v;
  long long int moregas;
} a[200020];
bool cmp(car x, car y) { return x.c < y.c; }
long long int cnm[200020];
long long int gas[200020];
using namespace std;
int main() {
  int n, k;
  long long int s, t;
  scanf("%d%d%I64d%I64d", &n, &k, &s, &t);
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &a[i].c, &a[i].v);
    a[i].moregas = a[i].v * (k + 1) - s;
  }
  sort(a + 1, a + 1 + n, cmp);
  for (int i = 1; i <= k; i++) {
    scanf("%I64d", &gas[i]);
  }
  if (t < s) {
    puts("-1");
    return 0;
  }
  long long int mingas = 0;
  sort(gas + 1, gas + 1 + k);
  for (int i = 1; i <= k - 1; i++) {
    mingas = max(gas[i + 1] - gas[i], mingas);
    cnm[i] = gas[i + 1] - gas[i];
  }
  mingas = max(gas[1], mingas);
  cnm[0] = gas[1];
  mingas = max(s - gas[k] + 1, mingas);
  cnm[k] = s - gas[k];
  int flag = 0;
  for (int i = 1; i <= n; i++) {
    if (a[i].v < mingas) {
      continue;
    }
    long long int spe = 0;
    for (int j = 0; j <= k; j++) {
      if (a[i].v > 2 * cnm[j]) {
        a[i].moregas -= (a[i].v - 2 * cnm[j]);
      }
    }
    spe = 2 * s - a[i].moregas;
    if (spe <= t) {
      printf("%d\n", a[i].c);
      flag = 1;
      break;
    }
  }
  if (flag == 0) {
    puts("-1");
  }
  return 0;
}
