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 n, k;
long long s, t, v[200010], c[200010], g[200010];
bool check(int x) {
  long long cap = 0;
  for (int i = 1; i <= n; ++i) {
    if (c[i] <= x) {
      cap = max(cap, v[i]);
    }
  }
  long long time = 0;
  for (int i = 1; i < k; ++i) {
    long long d = g[i + 1] - g[i];
    if (cap < d) {
      return false;
    }
    time += 3 * d - min(cap, 2 * d);
  }
  if (time <= t) {
    return true;
  } else {
    return false;
  }
}
void solve() {
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; ++i) {
    cin >> c[i] >> v[i];
  }
  g[1] = 0;
  for (int i = 1; i <= k; ++i) {
    cin >> g[i + 1];
  }
  ++k;
  g[++k] = s;
  sort(g + 1, g + k + 1);
  long long lo = 0, hi = 1e9 + 1;
  while (hi - lo > 1) {
    long long mid = (lo + hi) / 2;
    if (check(mid)) {
      hi = mid;
    } else {
      lo = mid;
    }
  }
  cout << hi << "\n";
}
int main() {
  int test = 1;
  for (; test; --test) {
    solve();
  }
}
