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>
const int N = 2e5 + 11;
long long gs[N], seg[N], n, k, s, t;
struct data {
  long long c, v;
  bool operator<(data x) const {
    if (v == x.v) return c < x.c;
    return v > x.v;
  }
} prop[N];
long long need_time(long long fuel, long long dist) {
  if (fuel < dist) return 5e9;
  long long d = fuel - dist;
  long long tt = dist * 2LL;
  tt -= std::min(dist, d);
  return tt;
}
bool check(long long fuel) {
  long long nt = 0LL;
  for (int i = 1; i <= k; i++) {
    nt += need_time(fuel, seg[i]);
  }
  return (nt <= t);
}
int main() {
  scanf("%lld%lld%lld%lld", &n, &k, &s, &t);
  for (int i = 1; i <= n; i++) scanf("%lld%lld", &prop[i].c, &prop[i].v);
  for (int i = 1; i <= k; i++) scanf("%lld", gs + i);
  std::sort(prop + 1, prop + n + 1);
  std::sort(gs + 1, gs + k + 1);
  gs[k + 1] = s;
  k++;
  seg[1] = gs[1];
  for (int i = 2; i <= k; i++) {
    seg[i] = gs[i] - gs[i - 1];
  }
  int lo = 1, hi = n;
  while (hi - lo > 1) {
    int m = (hi + lo) >> 1;
    if (check(prop[m].v))
      lo = m;
    else
      hi = m;
  }
  if (check(prop[lo].v))
    printf("%lld\n", prop[lo].c);
  else
    puts("-1");
}
