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 N, K, S, T, Max_D;
long long ans;
long long X, Y;
class rec {
 public:
  long long c, v;
} P[200010];
long long g[200010], D[200010];
bool cmpv(const rec &A, const rec &B) { return A.v < B.v; }
int main() {
  scanf("%I64d%I64d%I64d%I64d", &N, &K, &S, &T);
  for (long long i = 1; i <= N; i++) scanf("%I64d%I64d", &P[i].c, &P[i].v);
  sort(P + 1, P + N + 1, cmpv);
  for (long long i = 1; i <= K; i++) scanf("%I64d", &g[i]);
  sort(g + 1, g + K + 1);
  g[K + 1] = S;
  Max_D = 0;
  for (long long i = 1; i <= K + 1; i++) {
    D[i] = g[i] - g[i - 1];
    Max_D = max(Max_D, D[i]);
  }
  sort(D + 1, D + K + 2);
  long long x = 1;
  while (x <= N && P[x].v < Max_D) x++;
  X = 0;
  Y = 0;
  for (long long i = 1; i <= K + 1; i++) {
    long long xx = 2 * D[i] - P[x].v;
    long long yy = P[x].v - D[i];
    if (xx < 0) xx = 0, yy = D[i];
    X += xx;
    Y += yy;
  }
  long long j = 1;
  while (j <= K + 1 && 2 * D[j] < P[x].v) j++;
  ans = 2e9;
  if (2 * X + Y <= T) ans = min(ans, P[x].c);
  x++;
  while (x <= N) {
    Y += (long long)(K - j + 2) * (P[x].v - P[x - 1].v);
    X -= (long long)(K - j + 2) * (P[x].v - P[x - 1].v);
    while (j <= K + 1 && 2 * D[j] < P[x].v) {
      long long xx = 2 * D[j] - P[x].v;
      long long yy = P[x].v - D[j];
      X -= xx;
      Y -= yy;
      if (xx < 0) xx = 0, yy = D[j];
      X += xx;
      Y += yy;
      j++;
    }
    if (2 * X + Y <= T) ans = min(ans, P[x].c);
    x++;
  }
  cout << ans << endl;
}
