#include <bits/stdc++.h>
using namespace std;
struct car {
  long long v, c;
};
bool comp(const car &a, const car &b) { return a.v > b.v; }
long long g[202020];
car m[202020];
int n, k;
long long s, t;
bool gtime(int val) {
  long long cur(0), res(0);
  for (int i(0); i < k; ++i) {
    if (g[i] - cur > m[val].v) return false;
    long long dist(g[i] - cur);
    res += max(dist, 3 * dist - m[val].v);
    cur = g[i];
  }
  return res <= t;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> k >> s >> t;
  for (int i(0); i < n; ++i) cin >> m[i].c >> m[i].v;
  sort(m, m + n, comp);
  for (int i(0); i < k; ++i) cin >> g[i];
  g[k++] = s;
  sort(g, g + k);
  int l(0), r(n);
  while (l + 1 < r) {
    if (gtime((l + r) / 2)) {
      l = (l + r) / 2;
    } else
      r = (l + r) / 2;
  }
  if (!gtime(l)) {
    cout << -1;
    return 0;
  }
  long long ans(1e9 + 1);
  for (int i(0); i <= l; ++i) ans = min(ans, m[i].c);
  cout << ans;
}
