#include <bits/stdc++.h>
using namespace std;
const long long N = 2e5 + 10;
const long long LOGMAX = 11;
const long long inf = 1e9;
long long n, m, k, q;
long long b[N];
long long mn[N];
long long mx[N];
long long dp[N][2];
long long get(long long x, long long y) {
  long long lo = lower_bound(b, b + q, min(x, y)) - b;
  long long ans = 1e9;
  if (lo < q) ans = abs(b[lo] - x) + abs(b[lo] - y);
  if (lo > 0) ans = min(ans, abs(b[lo - 1] - x) + abs(b[lo - 1] - y));
  return ans;
}
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> m >> k >> q;
  for (long long i = 2; i <= n; ++i) {
    mn[i] = 1e9;
    mx[i] = -1e9;
  }
  mn[1] = mx[1] = 1;
  for (long long i = 0; i < k; ++i) {
    long long r, c;
    cin >> r >> c;
    mn[r] = min(mn[r], c);
    mx[r] = max(mx[r], c);
  }
  dp[1][1] = mx[1] - mn[1];
  dp[1][0] = 2 * dp[1][1];
  for (long long i = 0; i < q; ++i) {
    cin >> b[i];
  }
  long long last = 1;
  sort(b, b + q);
  for (long long i = 2; i <= n; ++i) {
    if (mx[i] > 0) {
      dp[i][0] = min(get(mn[last], mx[i]) + dp[last][0],
                     get(mx[last], mx[i]) + dp[last][1]) +
                 (i - last) + (mx[i] - mn[i]);
      dp[i][1] = min(get(mn[last], mn[i]) + dp[last][0],
                     get(mx[last], mn[i]) + dp[last][1]) +
                 (i - last) + (mx[i] - mn[i]);
      last = i;
    }
  }
  cout << min(dp[last][0], dp[last][1]) << '\n';
  return 0;
}
