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 * 5;
struct node {
  int c, v;
  bool operator<(const node &a) const {
    if (v == a.v) return c < a.c;
    return v < a.v;
  }
} sv[MAXN];
int g[MAXN];
long long n, k, s, t;
bool judge(long long v) {
  long long tot = 0, tmp;
  for (int i = k; i >= 1; i--) {
    tmp = v;
    long long dis = g[i] - g[i - 1];
    if (dis > v) return false;
    tmp -= dis;
    tot += 2 * dis;
    tot -= min(tmp, dis);
  }
  return tot <= t;
}
int main() {
  scanf("%lld%lld%lld%lld", &n, &k, &s, &t);
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &sv[i].c, &sv[i].v);
  }
  for (int i = 1; i <= k; i++) {
    scanf("%d", &g[i]);
  }
  k++;
  g[0] = 0, g[k] = s;
  sort(g + 1, g + 1 + k);
  sort(sv + 1, sv + 1 + n);
  long long l = 0, r = 1e9 + 7, ans = 1e9 + 7;
  while (l <= r) {
    long long m = (l + r) >> 1;
    if (judge(m)) {
      ans = min(ans, m);
      r = m - 1;
    } else {
      l = m + 1;
    }
  }
  node T;
  T.c = 0, T.v = ans;
  int pos = lower_bound(sv + 1, sv + 1 + n, T) - sv;
  if (pos == n + 1) return 0 * printf("-1\n");
  printf("%d\n", sv[pos].c);
  return 0;
}
