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 maxn = 2e5 + 9;
const long long mod = 1e9 + 7;
int n, k, nb = 0;
long long s, t;
long long cur, mx, sum, pre, res = -1;
long long c[maxn], v[maxn], g[maxn];
map<long long, long long> num, pree;
set<long long> st;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  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);
  for (int i = 0; i < k; i++) {
    num[g[i] - pre]++;
    st.insert(g[i] - pre);
    mx = max(mx, g[i] - pre);
    pre = g[i];
  }
  st.insert(s - pre);
  num[s - pre]++;
  mx = max(mx, s - pre);
  for (int i = 0; i < n; i++) {
    st.insert(v[i] / 2);
  }
  for (auto x : st) {
    nb += num[x];
    cur += num[x] * x;
    pree[x] = cur;
    num[x] = nb;
  }
  for (int i = 0; i < n; i++) {
    if (v[i] < mx) {
      continue;
    }
    long long f = num[v[i] / 2];
    long long ff = pree[v[i] / 2];
    long long cur = v[i] * (k + 1 - f) - (s - ff);
    if (ff + cur + (s - ff - cur) * 2 <= t) {
      res = ((res + 1) ? min(res, c[i]) : c[i]);
    }
  }
  cout << res << '\n';
  return 0;
}
