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;
long long n, k, s, t, i;
long long a[200010], b[200010], c[200010];
bool node(long long mid) {
  long long t1 = 0;
  long long s1 = c[0];
  if (s1 > mid) {
    return 0;
  } else if (s1 <= mid && s1 > (mid / (2.0))) {
    t1 += 3 * s1 - mid;
  } else {
    t1 += s1;
  }
  for (i = 1; i < k; i++) {
    s1 = c[i] - c[i - 1];
    if (s1 > mid) {
      return 0;
    } else if (s1 <= mid && s1 > (mid / (2.0))) {
      t1 += 3 * s1 - mid;
    } else {
      t1 += s1;
    }
  }
  s1 = s - c[k - 1];
  if (s1 > mid) {
    return 0;
  } else if (s1 <= mid && s1 > (mid / (2.0))) {
    t1 += 3 * s1 - mid;
  } else {
    t1 += s1;
  }
  if (t1 <= t) {
    return 1;
  } else {
    return 0;
  }
}
int main() {
  long long r, l;
  r = -1;
  l = 1000000000000;
  cin >> n >> k >> s >> t;
  for (i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    r = max(r, b[i]);
    l = min(l, b[i]);
  }
  for (i = 0; i < k; i++) {
    cin >> c[i];
  }
  if (k > 1) {
    sort(c, c + k);
  }
  long long mid;
  while (r >= l) {
    mid = (r + l) / 2;
    if (node(mid) == 1) {
      r = mid - 1;
    } else {
      l = mid + 1;
    }
  }
  long long ans = 0;
  if (node(r) == 1) {
    ans = r;
  } else if (node(l) == 1) {
    ans = l;
  } else {
    ans = 0x3f3f3f3f;
  }
  long long ans1 = 0x3f3f3f3f;
  for (i = 0; i < n; i++) {
    if (b[i] >= ans) {
      ans1 = min(ans1, a[i]);
    }
  }
  if (ans1 == 0x3f3f3f3f) {
    cout << -1 << endl;
  } else {
    cout << ans1 << endl;
  }
  return 0;
}
