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 MAX_N = (int)2e5 + 123;
const int inf = (int)1e9 + 123;
int n, k, second, t;
int c[MAX_N], v[MAX_N];
long long min_time(int len, int cap) {
  if (len > cap) return inf;
  int now = cap - len;
  now = min(now, len);
  return 1ll * now + 2ll * (len - now);
}
int calc(vector<int> &len, int cost, int v) {
  long long all = 0;
  for (auto i : len) {
    all += min_time(i, v);
  }
  if (all <= t) return cost;
  return inf;
}
int g[MAX_N];
int main() {
  cin >> n >> k >> second >> t;
  int ans = inf;
  for (int i = 1; i <= n; i++) cin >> c[i] >> v[i];
  vector<int> len;
  for (int i = 1; i <= k; i++) cin >> g[i];
  sort(g + 1, g + k + 1);
  for (int i = 1; i <= k; i++) len.push_back(g[i] - g[i - 1]);
  len.push_back(second - g[k]);
  for (int i = 1; i <= n; i++) ans = min(ans, calc(len, c[i], v[i]));
  cout << (ans == inf ? -1 : ans);
  return 0;
}
