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 long long inf = (1LL << 60);
int n, k;
long long s, t;
long long c[200005], v[200005];
long long g[200005];
long long d[200005];
long long d2[200005];
long long sum[200005];
int tot;
bool check(int x) {
  int pos = upper_bound(d2, d2 + tot, v[x]) - 1 - d2;
  long long tim = sum[pos];
  tim = tim + (3LL * (sum[tot - 1] - sum[pos]) - v[x] * (tot - 1 - pos));
  return tim <= t;
}
int main() {
  scanf("%d%d%I64d%I64d", &n, &k, &s, &t);
  for (int i = 0; i < n; i++) scanf("%I64d%I64d", &c[i], &v[i]);
  long long ans = inf;
  for (int i = 0; i < k; i++) scanf("%I64d", &g[i]);
  sort(g, g + k);
  d[0] = g[0];
  for (int i = 1; i < k; i++) d[i] = g[i] - g[i - 1];
  d[k] = s - g[k - 1];
  tot = k + 1;
  sort(d, d + tot);
  for (int i = 0; i < tot; i++) d2[i] = d[i] * 2;
  sum[0] = d[0];
  for (int i = 1; i < tot; i++) sum[i] = sum[i - 1] + d[i];
  for (int i = 0; i < n; i++) {
    if (v[i] < d[tot - 1]) continue;
    if (check(i)) ans = min(ans, c[i]);
  }
  printf("%I64d\n", ans == inf ? -1 : ans);
  return 0;
}
