#include <bits/stdc++.h>
using namespace std;
inline long long gcd(long long a, long long b) {
  while (b != 0) {
    long long c = a % b;
    a = b;
    b = c;
  }
  return a < 0 ? -a : a;
}
inline long long lowbit(long long x) { return x & (-x); }
const double PI = 3.14159265358979323846;
const int inf = 0x3f3f3f3f;
const long long INF = 0x3f3f3f3f3f3f3f3f;
const long long mod = 100000007;
inline long long rd() {
  long long x = 0, f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = (x << 3) + (x << 1) + (ch ^ 48);
    ch = getchar();
  }
  return x * f;
}
const double eps = 1e-6;
const int M = 1e6 + 10;
const int N = 1e6 + 10;
int L[N], R[N];
long long ansl[N], ansr[N];
set<int> pos;
set<int>::iterator lt, rt;
int n, m, k, q;
int num[N];
int main() {
  n = rd(), m = rd(), k = rd(), q = rd();
  memset(L, inf, sizeof L);
  for (int i = 1; i <= k; i++) {
    int x = rd(), y = rd();
    L[x] = min(L[x], y);
    R[x] = max(R[x], y);
    num[x]++;
  }
  for (int i = 1; i <= q; i++) {
    pos.insert(rd());
  }
  if (num[1]) {
    ansr[1] = (long long)R[1] - 1;
    ansl[1] = ansr[1] + R[1] - L[1];
  } else {
    L[1] = 1, R[1] = 1;
    ansl[1] = ansr[1] = 0;
  }
  int sum = num[1];
  long long ans = 0;
  for (int i = 2; i <= n + 1; i++) {
    if (sum == k) {
      ans = min(ansl[i - 1], ansr[i - 1]);
      break;
    }
    if (!num[i]) {
      ansl[i] = ansl[i - 1] + 1;
      ansr[i] = ansr[i - 1] + 1;
      L[i] = L[i - 1];
      R[i] = R[i - 1];
    } else {
      rt = pos.lower_bound(L[i - 1]);
      lt = rt;
      if (lt != pos.begin()) lt--;
      int l1 = min(abs(*lt - L[i - 1]) + abs(*lt - R[i]),
                   abs(*rt - L[i - 1]) + abs(*rt - R[i]));
      int r1 = min(abs(*lt - L[i - 1]) + abs(*lt - L[i]),
                   abs(*rt - L[i - 1]) + abs(*rt - L[i]));
      rt = pos.lower_bound(R[i - 1]);
      lt = rt;
      if (lt != pos.begin()) lt--;
      int l2 = min(abs(*lt - R[i - 1]) + abs(*lt - R[i]),
                   abs(*rt - R[i - 1]) + abs(*rt - R[i]));
      int r2 = min(abs(*lt - R[i - 1]) + abs(*lt - L[i]),
                   abs(*rt - R[i - 1]) + abs(*rt - L[i]));
      ansl[i] =
          (long long)min(ansl[i - 1] + l1, ansr[i - 1] + l2) + R[i] - L[i] + 1;
      ansr[i] =
          (long long)min(ansl[i - 1] + r1, ansr[i - 1] + r2) + R[i] - L[i] + 1;
    }
    sum += num[i];
  }
  cout << ans << endl;
}
