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 N = 2e6 + 100, M = 20, LG = 30, base = 2;
const int MOD = 1e9 + 7, mod = 1e9 + 9;
const long long INF = 1e13, inf = 1e18;
long long n, k, s, t, l, mid, r = INF, ans = INF, m;
long long c[N], v[N], g[N];
bool check(long long x) {
  m = 0;
  for (int i = 0; i < k; i++) {
    if (g[i] > x) return 0;
    if (2 * g[i] <= x) {
      m += g[i];
      continue;
    }
    m += 3 * g[i] - x;
  }
  return (m <= t);
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  ;
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) cin >> c[i] >> v[i];
  for (int i = 0; i < k; i++) cin >> g[i];
  sort(g, g + k), g[k] = s, k++;
  for (int i = k - 1; i > 0; i--) g[i] -= g[i - 1];
  while (r - l > 1) {
    mid = (l + r) / 2;
    if (check(mid))
      r = mid;
    else
      l = mid;
  }
  for (int i = 0; i < n; i++)
    if (v[i] >= r) ans = min(ans, c[i]);
  return cout << (ans == INF ? -1 : ans), 0;
}
