#include <bits/stdc++.h>
using namespace std;
inline int read() {
  int x = 0, f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
int c[200100], v[200100], g[200100];
int n, k, s, t;
bool check(long long x) {
  long long tt = 0;
  for (int i = 1; i <= k + 1; i++) {
    int dist = g[i] - g[i - 1];
    if (x >= dist * 2) {
      tt += dist;
    } else if (x >= dist) {
      tt += (x - dist) + (dist - x + dist) * 2;
    } else
      return false;
  }
  return tt <= t;
}
int main() {
  n = read();
  k = read();
  s = read();
  t = read();
  for (int i = 1; i <= n; i++) {
    c[i] = read();
    v[i] = read();
  }
  for (int i = 1; i <= k; i++) g[i] = read();
  sort(g + 1, g + 1 + k);
  g[k + 1] = s;
  long long l = 1, r = 2e9, mid;
  while (l + 5 < r) {
    mid = (l + r) >> 1;
    if (check(mid))
      r = mid;
    else
      l = mid;
  }
  int lb = l;
  for (int i = l; i <= r; i++) {
    if (check(i)) {
      lb = i;
      break;
    }
  }
  long long mn = 2e9;
  for (int i = 1; i <= n; i++) {
    if (v[i] >= lb) mn = min(mn, 1ll * c[i]);
  }
  if (mn == 2e9) mn = -1;
  cout << mn << endl;
  return 0;
}
