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;
struct car {
  long long c, v;
} num[200005];
long long g[200005];
int cmp(car a, car b) {
  if (a.c == b.c) return a.v > b.v;
  return a.c < b.c;
}
long long check(long long a, long long k, long long t) {
  long long time = 0;
  for (long long i = 1; i <= k; i++) {
    if (a < g[i] - g[i - 1]) return 0;
    time += 2 * (g[i] - g[i - 1]);
    time -= min(a - (g[i] - g[i - 1]), g[i] - g[i - 1]);
  }
  return time <= t;
}
long long binary(long long l, long long r, long long k, long long t) {
  long long mid;
  while (l <= r) {
    mid = (l + r) / 2;
    if (!check(mid, k, t)) {
      l = mid + 1;
    } else {
      r = mid - 1;
    }
  }
  return l;
}
int main() {
  long long n, k, s, t, stal, star, flag, ans;
  while (~scanf("%lld %lld %lld %lld", &n, &k, &s, &t)) {
    flag = g[0] = 0;
    for (int i = 0; i < n; i++) scanf("%lld %lld", &num[i].c, &num[i].v);
    for (int i = 1; i <= k; i++) scanf("%lld", &g[i]);
    sort(g, g + k + 1);
    g[++k] = s;
    sort(num, num + n, cmp);
    ans = binary(1, 1e9, k, t);
    for (int i = 0; i < n; i++) {
      if (num[i].v >= ans) {
        printf("%lld\n", num[i].c);
        flag = 1;
        break;
      }
    }
    if (!flag) printf("-1\n");
  }
}
