#include <bits/stdc++.h>
using namespace std;
using LL = long long;
using PII = pair<int, int>;
const int N = 2e5 + 10;
const LL INF = 1e18;
vector<PII> adj[2 * N];
LL dist[2 * N];
void dijkstra(int src) {
  fill(dist, dist + 2 * N, INF);
  dist[src] = 0;
  priority_queue<PII> heap;
  heap.emplace(0, src);
  while (!heap.empty()) {
    int u = heap.top().second;
    heap.pop();
    for (auto& e : adj[u]) {
      int v = e.second, w = e.first;
      if (dist[v] > dist[u] + w) {
        dist[v] = dist[u] + w;
        heap.emplace(-dist[v], v);
      }
    }
  }
}
void add_edge(int u, int v, int w) { adj[u].emplace_back(w, v); }
vector<int> rows[N];
int safe[N];
int sz[N];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, m, k, q;
  cin >> n >> m >> k >> q;
  for (int i = 0; i < k; i++) {
    int r, c;
    cin >> r >> c;
    rows[r - 1].push_back(c - 1);
  }
  for (int i = 0; i < n; i++) {
    sort(rows[i].begin(), rows[i].end());
    if (i > 0) {
      sz[i] = sz[i - 1] + rows[i - 1].size();
    } else {
      if (rows[0].empty() || rows[0][0] != 0) {
        rows[0].insert(rows[0].begin(), 0);
        k++;
      }
    }
  }
  for (int i = 0; i < q; i++) {
    cin >> safe[i];
    safe[i]--;
  }
  sort(safe, safe + q);
  for (int i = 0; i < n; i++) {
    if (rows[i].empty()) continue;
    int width = rows[i].back() - rows[i][0];
    for (int x = 0; x < (int)rows[i].size(); x++) {
      add_edge(sz[i] + x, sz[i] + k, rows[i].back() - rows[i][x] + width);
      add_edge(sz[i] + x, sz[i] - 1 + rows[i].size() + k,
               rows[i][x] - rows[i][0] + width);
    }
    int j = i + 1;
    while (j < n && rows[j].empty()) j++;
    if (j == n) break;
    for (int x = 0; x < (int)rows[i].size(); x++) {
      int u = sz[i] + x + k;
      if (rows[i][x] >= safe[0]) {
        int col = *(upper_bound(safe, safe + q, rows[i][x]) - 1);
        if (rows[j][0] <= col) {
          auto it = upper_bound(rows[j].begin(), rows[j].end(), col) - 1;
          add_edge(u, sz[j] + (it - rows[j].begin()),
                   abs(rows[i][x] - col) + (j - i) + abs(*it - col));
        }
        if (rows[j].back() >= col) {
          auto it = lower_bound(rows[j].begin(), rows[j].end(), col);
          add_edge(u, sz[j] + (it - rows[j].begin()),
                   abs(rows[i][x] - col) + (j - i) + abs(*it - col));
        }
      }
      if (rows[i][x] <= safe[q - 1]) {
        int col = *lower_bound(safe, safe + q, rows[i][x]);
        if (rows[j][0] <= col) {
          auto it = upper_bound(rows[j].begin(), rows[j].end(), col) - 1;
          add_edge(u, sz[j] + (it - rows[j].begin()),
                   abs(rows[i][x] - col) + (j - i) + abs(*it - col));
        }
        if (rows[j].back() >= col) {
          auto it = lower_bound(rows[j].begin(), rows[j].end(), col);
          add_edge(u, sz[j] + (it - rows[j].begin()),
                   abs(rows[i][x] - col) + (j - i) + abs(*it - col));
        }
      }
    }
  }
  dijkstra(0);
  int lr = n - 1;
  while (rows[lr].empty()) lr--;
  LL ans = INF;
  for (int i = sz[lr]; i < k; i++) {
    ans = min(ans, dist[i + k]);
  }
  cout << ans << endl;
  return 0;
}
