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 INF = 0x3f3f3f3f;
const long long LLINF = 0x3f3f3f3f3f3f3f3f;
long long a[200200][2];
long long b[200200];
bool pd(long long now, int n, int t) {
  long long sum = 0;
  long long pre = 0;
  for (int i = 0; i <= n; ++i) {
    long long jl = b[i] - pre;
    if (jl > now) return false;
    long long temp = now - jl;
    sum += max(jl, 2 * jl - temp);
    pre = b[i];
  }
  if (sum <= t) return true;
  return false;
}
long long erfen(long long l, long long r, int n, int t) {
  while (l < r) {
    long long mid = (l + r) >> 1;
    if (pd(mid, n, t))
      r = mid;
    else
      l = mid + 1;
  }
  return l;
}
int main() {
  long long n, m, s, t;
  scanf("%I64d%I64d%I64d%I64d", &n, &m, &s, &t);
  for (int i = 0; i < n; ++i) scanf("%I64d%I64d", &a[i][0], &a[i][1]);
  for (int i = 0; i < m; ++i) scanf("%I64d", b + i);
  if (s > t) {
    printf("-1\n");
    return 0;
  }
  b[m] = s;
  sort(b, b + m + 1);
  long long ma = erfen(1, 2 * s, m, t);
  long long ans = LLINF;
  for (int i = 0; i < n; ++i)
    if (a[i][1] >= ma) ans = min(ans, a[i][0]);
  if (ans == LLINF) ans = -1;
  printf("%I64d\n", ans);
  return 0;
}
