#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int N = 202020;

int n, m, k, P, a[N], b[N], g[N], vis[N];
pair<int, int> c[N], d[2 * N];

int main() {
    cin.tie(0); ios_base::sync_with_stdio(0);
    cin >> n >> m >> k >> P;
    for (int i = 0; i < m; i++) {
        int x; cin >> x;
        cin >> a[x - 1];
    }
    for (int i = 0; i < k; i++) {
        int x; cin >> x;
        b[x - 1] = 1;
    }

    auto go = [&](int x) {
        return (x == n - 1) ? 0 : x + 1;
    };
    auto rev = [&](int x) {
        return (x == 0) ? n - 1 : x - 1;
    };
    auto dist = [&](int i, int j) {
        return (j >= i) ? j - i : n + j - i;
    };

    ll L = 0, R = 2e10;
    while (L < R) {
        ll M = (L + R) / 2;
        ll s = 0, p = 0, sz = 0;
        for (int i = 0, j = 0; i < n; i++) {
            if (i == j) {
                if (!a[j]) p = j;
                j = go(j);
                s += a[j] + 1;
            }
            while (i != j && s <= M) {
                if (!a[j]) p = j;
                j = go(j);
                s += a[j] + 1;
            }
            if (b[i]) c[sz++].second = p;
            if (i != n - 1) {
                s -= a[go(i)] + 1;
            }
        }
        s = 0; p = 0;
        for (int i = n - 1, j = n - 1; i >= 0; i--) {
            if (i == j) {
                if (!a[j]) p = j;
                j = rev(j);
                s += a[j] + 1;
            }
            while (i != j && s <= M) {
                if (!a[j]) p = j;
                j = rev(j);
                s += a[j] + 1;
            }
            if (b[i]) c[--sz].first = p;
            if (i != 0) {
                s -= a[rev(i)] + 1;
            }
        }
        sz = 0; int tz = 0;
        for (int i = 0; i < n; i++) if (b[i]) {
            auto [l, r] = c[sz++];
            if (dist(i, r) + dist(l, i) >= n - 1) {
                continue;
            }
            swap(c[tz++], c[sz - 1]);
        }
        if (tz == 0) {
            R = M;
            continue;
        }
        sz = 0;
        for (int i = 0; i < tz; i++) {
            while (i && c[i].first < c[i - 1].first) {
                c[i].first += n;
                c[i].second += n;
            }
            while (c[i].second < c[i].first) {
                c[i].second += n;
            }
            while (sz && c[i].second <= d[sz - 1].second) {
                --sz;
            }
            d[sz++] = c[i];
        }
        for (int i = 0; i < sz; i++) {
            d[i + sz] = d[i];
            d[i + sz].first += n;
            d[i + sz].second += n;
        }

        for (int i = 0, j = 0; i < sz; i++) {
            if (i == j) ++j;
            while (j < 2 * sz && d[j].first <= d[i].second) {
                ++j;
            }
            g[i] = j % sz;
        }
        bool f = false;
        for (int i = 0; i < sz; i++) {
            if (i == g[i]) f = true;
            if (dist(d[i].first, d[g[i]].first) + dist(d[g[i]].first, d[g[i]].second) >= n) f = true;
        }
        if (f) {
            R = M;
            continue;
        }
        
        int y = -1;
        fill(vis, vis + sz, 0);
        for (int i = 0; i < sz; i++) {
            if (vis[i]) continue;
            int x = i;
            while (!vis[x]) {
                vis[x] = 1;
                x = g[x] % sz;
                if (vis[x] == 1) {
                    y = x;
                }
            }
            x = i;
            while (vis[x] == 1) {
                vis[x] = 2;
                x = g[x] % sz;
            }
        }
        
        int ans = 0, x = y, t = dist(d[y].first, d[y].second);
        while (t < n) {
            ++ans;
            t += dist(d[x].second, d[g[x]].second);
            x = g[x];
        }
        if (ans <= P) R = M;
        else L = M + 1;
    }
    cout << L;
}