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>
#pragma comment(linker, "/STACK:32000000")
using namespace std;
inline bool read(int& val) { return scanf("%d", &val) != -1; }
inline bool read(long long& val) { return scanf("%I64d", &val) != -1; }
inline bool read(double& val) { return scanf("%lf", &val) != -1; }
inline bool read(char* val) { return scanf("%s", val) != -1; }
template <class T1, class T2>
inline bool read(T1& a, T2& b) {
  return read(a) && read(b);
}
template <class T1, class T2, class T3>
inline bool read(T1& a, T2& b, T3& c) {
  return read(a) && read(b) && read(c);
}
template <class T1, class T2, class T3, class T4>
inline bool read(T1& a, T2& b, T3& c, T4& d) {
  return read(a) && read(b) && read(c) && read(d);
}
template <class T1, class T2, class T3, class T4, class T5>
inline bool read(T1& a, T2& b, T3& c, T4& d, T5& e) {
  return read(a) && read(b) && read(c) && read(d) && read(e);
}
const int N = 1111111;
struct car {
  int c, v;
  friend bool operator<(car a, car b) { return a.c < b.c; }
};
int G[N];
car cars[N];
int n, k, s, t;
int get(int v, int s) {
  if (s * 2 < v) return s;
  if (v < s) return -1;
  int a = v - s, b = s - a;
  return a + 2 * b;
}
int f(int x) {
  int v = cars[x].v;
  int ret = get(v, G[0]);
  if (ret == -1) return 0;
  G[k] = s;
  for (int i = 0, _ = (k); i < _; ++i) {
    int val = get(v, G[i + 1] - G[i]);
    if (val == -1) return 0;
    ret += val;
  }
  return ret <= t;
}
template <class F, class T, class V>
T lower_bound(F f, T l, T r, V val) {
  while (l < r) {
    T m = l + (r - l) / 2;
    if (f(m) < val)
      l = m + 1;
    else
      r = m;
  }
  return l;
}
int main() {
  read(n, k, s, t);
  for (int i = 0, _ = (n); i < _; ++i) read(cars[i].c, cars[i].v);
  for (int i = 0, _ = (k); i < _; ++i) read(G[i]);
  sort(G, G + k);
  sort(cars, cars + n);
  int m = 0;
  int maxv = 0;
  for (int i = 0, _ = (n); i < _; ++i)
    if (cars[i].v > maxv) {
      cars[m++] = cars[i];
      maxv = cars[i].v;
    }
  int x = lower_bound(f, 0, m, 1);
  printf("%d\n", cars[x].c);
  return 0;
}
