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;
int main() {
  unsigned long long int n, k, s, t, c[200005], v[200005], g,
      gmax = 0, total, i, j, f, tg = 0, ps, lit, x = 999999999999999;
  cin >> n >> k >> s >> t;
  for (i = 0; i < n; i++) {
    cin >> c[i] >> v[i];
  }
  for (i = 0; i < k; i++) {
    cin >> g;
    if (gmax < g) {
      gmax = g;
    }
    tg += g;
  }
  if (t < s) {
    cout << "-1" << endl;
  } else if (s <= t) {
    f = t - s;
    ps = s - tg;
    if (ps <= gmax) {
      if (gmax <= f) {
        lit = gmax;
      } else {
        lit = f + ((gmax - f) * 2);
      }
    } else {
      if (ps <= f) {
        lit = ps;
      } else {
        lit = f + ((ps - f) * 2);
      }
    }
  }
  for (i = 0; i < n; i++) {
    if (lit <= v[i]) {
      if (c[i] < x) {
        x = c[i];
      }
    }
  }
  if (x != 999999999999999)
    cout << x << endl;
  else {
    cout << "-1" << endl;
  }
}
