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;
int GLL(long long& x) { return scanf("%lld", &x); }
int GI(int& x) { return scanf("%d", &x); }
int n, k;
long long s, t;
const int MAXN = 200010;
long long c[MAXN], v[MAXN], g[MAXN];
bool check(long long x) {
  long long tm = 0;
  long long prev = 0;
  for (int i = 0; i < (int)(k + 1); i++) {
    long long delta = g[i] - prev;
    if (x < delta) return false;
    tm += 2 * delta - min(delta, x - delta);
    prev = g[i];
  }
  return (tm <= t);
}
int main() {
  GI(n);
  GI(k);
  GLL(s);
  GLL(t);
  for (int i = 0; i < (int)(n); i++) {
    GLL(c[i]);
    GLL(v[i]);
  }
  for (int i = 0; i < (int)(k); i++) {
    GLL(g[i]);
  }
  g[k] = s;
  sort(g, g + k + 1);
  long long lo = 0;
  long long hi = 2000000000 + 5;
  long long res = 2000000000 + 5;
  while (lo <= hi) {
    long long mid = (lo + hi) / 2;
    if (check(mid)) {
      res = mid;
      hi = mid - 1;
    } else {
      lo = mid + 1;
    }
  }
  long long ans = 2000000000;
  for (int i = 0; i < (int)(n); i++) {
    if (v[i] >= res) {
      ans = min(ans, c[i]);
    }
  }
  if (ans == 2000000000) {
    printf("-1\n");
  } else {
    printf("%lld\n", ans);
  }
  return 0;
}
