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;
long long spf[100];
long long fac[100];
void sieve() {
  spf[1] = 1;
  for (long long i = 2; i < 100; i++) spf[i] = i;
  for (long long i = 4; i < 100; i += 2) spf[i] = 2;
  for (long long i = 3; i * i < 100; i++) {
    if (spf[i] == i) {
      for (long long j = i * i; j < 100; j += i)
        if (spf[j] == j) spf[j] = i;
    }
  }
}
map<long long, long long> getfactor(long long a) {
  map<long long, long long> m;
  while (a > 1) {
    m[spf[a]]++;
    a /= spf[a];
  }
  return m;
}
long long power(long long x, long long y, long long p) {
  long long res = 1;
  x = x % p;
  if (x == 0) return 0;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
long long gcd(long long a, long long b) {
  if (a == 0) return b;
  return gcd(b % a, a);
}
long long inverse(long long a, long long p) { return power(a, p - 2, p); }
long long ncr(long long n, long long r, long long p) {
  if (r == 0) return 1;
  return (fac[n] * inverse(fac[r], p) % p * inverse(fac[n - r], p) % p) % p;
}
bool check(long long val, long long t, long long use[], long long k) {
  if (use[k] > val) return false;
  long long sum = 0;
  for (long long i = 0; i <= k; i++) {
    if (use[i] * 2 <= val)
      sum += use[i];
    else if (use[i] * 2 > val) {
      sum += val - use[i] + (2 * use[i] - val) * 2;
    }
  }
  if (sum <= t)
    return true;
  else
    return false;
}
void solve() {
  long long n, k, s, t;
  cin >> n >> k >> s >> t;
  vector<pair<long long, long long> > p(n);
  for (long long i = 0; i < n; i++) {
    cin >> p[i].second;
    cin >> p[i].first;
  }
  long long g[k];
  for (long long i = 0; i < k; i++) cin >> g[i];
  sort(g, g + k);
  long long use[k + 1];
  for (long long i = 0; i < k - 1; i++) use[i] = abs(g[i] - g[i + 1]);
  use[k - 1] = g[0] - 0;
  use[k] = s - g[k - 1];
  sort(use, use + k + 1);
  long long l = 1, r = 1e9;
  long long ans = 0;
  while (r >= l) {
    long long mid = (l + r) / 2;
    if (check(mid, t, use, k)) {
      ans = mid;
      r = mid - 1;
    } else
      l = mid + 1;
  }
  if (ans <= 0) cout << -1 << endl;
  long long flag = 1e18;
  for (long long i = 0; i < n; i++)
    if (p[i].first >= ans) {
      flag = min(flag, p[i].second);
    }
  if (flag != 1e18)
    cout << flag;
  else
    cout << -1 << endl;
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long t = 1;
  while (t--) {
    solve();
  }
}
