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 MAX_N = 200000;
const int MAX_K = 200000;
const int INF = 1 << 30;
const long long LINF = 1LL << 62;
int cs[MAX_N], vs[MAX_N], gs[MAX_K];
inline int calct(int v, int d) {
  int d0 = max(0, 2 * d - v);
  return (d0 > v) ? INF : d0 + d;
}
long long check(int k, int s, int v) {
  int t0 = calct(v, gs[0]), tk = calct(v, s - gs[k - 1]);
  if (t0 >= INF || tk >= INF) return LINF;
  long long sum = (long long)t0 + tk;
  for (int i = 1; i < k; i++) {
    int ti = calct(v, gs[i] - gs[i - 1]);
    if (ti >= INF) return LINF;
    sum += ti;
  }
  return sum;
}
int main() {
  int n, k, s, t;
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = 0; i < n; i++) scanf("%d%d", cs + i, vs + i);
  for (int i = 0; i < k; i++) scanf("%d", gs + i);
  sort(gs, gs + k);
  int v0 = 0, v1 = s * 2;
  while (v0 + 1 < v1) {
    int v = ((long long)v0 + v1) / 2;
    if (check(k, s, v) <= t)
      v1 = v;
    else
      v0 = v;
  }
  int minc = INF;
  for (int i = 0; i < n; i++)
    if (v1 <= vs[i] && minc > cs[i]) minc = cs[i];
  printf("%d\n", (minc >= INF) ? -1 : minc);
  return 0;
}
