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, s, t;
const int maxn = 2e5 + 5;
int c[maxn], v[maxn];
int g[maxn];
bool check(int V) {
  long long ans = 0;
  for (int i = 1; i <= k; i++) {
    int S = g[i] - g[i - 1];
    int t2 = min(S, V - S);
    if (t2 < 0) return false;
    int t1 = 2 * S - 2 * t2;
    if (t1 < 0) return false;
    ans += (t1 + t2);
  }
  return ans <= (long long)t;
}
int main() {
  cin >> n >> k >> s >> t;
  int l = 1e9 + 5, r = -1;
  for (int i = 1; i <= n; i++)
    scanf("%d%d", c + i, v + i), l = min(l, v[i]), r = max(r, v[i]);
  for (int i = 1; i <= k; i++) scanf("%d", g + i);
  sort(g + 1, g + 1 + k);
  g[k + 1] = s;
  k++;
  g[0] = 0;
  while (l < r) {
    int mid = (l + r) >> 1;
    if (check(mid)) {
      r = mid;
    } else {
      l = mid + 1;
    }
  }
  if (!check(l)) {
    printf("-1\n");
  } else {
    int mc = 1e9 + 5;
    for (int i = 1; i <= n; i++) {
      if (v[i] >= l) mc = min(mc, c[i]);
    }
    if (mc == 1e9 + 5)
      printf("-1\n");
    else
      printf("%d\n", mc);
  }
  return 0;
}
