#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const long long INF = 0x3f3f3f3f3f3f3f3fLL;
const double PI = acos(-1.0);
const long double eps = 1e-10;
const int mod = 1e9 + 7;
const int N = 2e5 + 10;
const int M = 6e4 + 10;
const long long mm = (1LL << 32);
template <class T>
inline void read(T &x) {
  x = 0;
  char c = getchar();
  bool f = 0;
  for (; !isdigit(c); c = getchar()) f ^= c == '-';
  for (; isdigit(c); c = getchar()) x = x * 10 + (c ^ 48);
  x = f ? -x : x;
}
template <class T>
inline void write(T x) {
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  T y = 1;
  int len = 1;
  for (; y <= x / 10; y *= 10) ++len;
  for (; len; --len, x %= y, y /= 10) putchar(x / y + 48);
}
long long qpow(long long a, long long b, long long MOD) {
  long long ans = 1;
  while (b) {
    if (b & 1) ans = (ans * a) % MOD;
    b >>= 1;
    a = (a * a) % MOD;
  }
  return ans;
}
int n, m, k, q;
long long dp[N][2], maxn[N][2];
int b[N];
long long trans(int u, int du, int v, int dv) {
  int p = lower_bound(b + 1, b + 1 + q, maxn[u][du]) - b;
  long long rt = INF;
  if (p <= q) {
    rt = abs(maxn[u][du] - b[p]) + abs(maxn[v][dv ^ 1] - b[p]) +
         abs(maxn[v][dv] - maxn[v][dv ^ 1]);
  }
  p = upper_bound(b + 1, b + 1 + q, maxn[u][du]) - b - 1;
  if (p)
    rt = min(rt, abs(maxn[u][du] - b[p]) + abs(maxn[v][dv ^ 1] - b[p]) +
                     abs(maxn[v][dv] - maxn[v][dv ^ 1]));
  return rt;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> m >> k >> q;
  for (int i = 1; i <= n; ++i) maxn[i][0] = INF, maxn[i][1] = -INF;
  for (int i = 1; i <= k; ++i) {
    long long x, y;
    cin >> x >> y;
    maxn[x][0] = min(maxn[x][0], y);
    maxn[x][1] = max(maxn[x][1], y);
  }
  for (int i = 1; i <= q; ++i) cin >> b[i];
  maxn[1][0] = 1;
  maxn[1][1] = max(maxn[1][1], 1LL);
  sort(b + 1, b + 1 + q);
  memset(dp, INF, sizeof(dp));
  dp[1][0] = abs(maxn[1][1] - 1) + abs(maxn[1][1] - maxn[1][0]);
  dp[1][1] = abs(maxn[1][1] - 1);
  int j = 1;
  for (int i = 2; i <= n; ++i) {
    if (maxn[i][0] == INF) continue;
    dp[i][0] = min(dp[i][0], dp[j][0] + trans(j, 0, i, 0) + i - j);
    dp[i][0] = min(dp[i][0], dp[j][1] + trans(j, 1, i, 0) + i - j);
    dp[i][1] = min(dp[i][1], dp[j][0] + trans(j, 0, i, 1) + i - j);
    dp[i][1] = min(dp[i][1], dp[j][1] + trans(j, 1, i, 1) + i - j);
    j = i;
  }
  cout << min(dp[j][0], dp[j][1]) << endl;
  return 0;
}
