#include <bits/stdc++.h>
using namespace std;
void upi(long long &_a, long long _b) { _a = min(_a, _b); }
void upa(long long &_a, long long _b) { _a = max(_a, _b); }
const long long nmax = 2e5 + 16;
long long n, k, s, t, g[nmax], l, r, m, res, now, rr;
bool ok(long long x);
long long bs(long long lv, long long rv, long long x);
long long bs1(long long l, long long r, long long x);
pair<long long, long long> a[nmax];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n >> k >> s >> t;
  for (long long i = 1; i <= n; i++) cin >> a[i].second >> a[i].first;
  for (long long i = 1; i <= k; i++) cin >> g[i];
  g[0] = 0, g[k + 1] = s;
  sort(g + 1, g + k + 1);
  sort(a + 1, a + n + 1);
  l = 1, r = 1e9, res = 1e9 + 16;
  while (l <= r) {
    m = (l + r) >> 1;
    if (ok(m)) {
      res = m;
      r = m - 1;
    } else
      l = m + 1;
  }
  if (a[n].first < res) return cout << -1, 0;
  now = bs1(1, n, res), rr = a[now].second;
  for (long long i = now + 1; i <= n; i++) upi(rr, a[i].second);
  cout << rr;
}
bool ok(long long x) {
  long long time = 0, now, idx, nxt;
  for (long long i = 0; i <= k; i++) {
    now = g[i] + 1, nxt = g[i + 1];
    idx = bs(now, nxt, x);
    if (idx == -1) return 0;
    time += (idx - now + 1) + (nxt - idx) * 2;
  }
  return time <= t;
}
long long bs(long long lv, long long rv, long long x) {
  long long l = lv - 1, r = rv, m, res = -1;
  while (l <= r) {
    m = (l + r) >> 1;
    if ((m - lv + 1) * 2 + (rv - m) <= x) {
      res = m;
      l = m + 1;
    } else
      r = m - 1;
  }
  return res;
}
long long bs1(long long l, long long r, long long x) {
  long long res;
  while (l <= r) {
    long long m = (l + r) >> 1;
    if (a[m].first >= x) {
      res = m;
      r = m - 1;
    } else
      l = m + 1;
  }
  return res;
}
