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

typedef long long ll;
const int N = 202020;

int n, m, k, p, a[N], b[N], psum[3 * N];
ll cr[20][N], pr[20][N], cl[20][N], pl[20][N];
pair<int, int> tmp[N], c[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];
    }
    ll s = 0;
    for (int i = 0, j = 0; i < n; i++) {
        if (i == j) {
            j = (j + 1) % n;
            s += a[j] + 1;
        }
        while (i != j && a[j]) {
            j = (j + 1) % n;
            s += a[j] + 1;
        }
        pr[0][i] = j;
        cr[0][i] = s;
        if (i != n - 1) {
            s -= a[i + 1] + 1;
        }
    }
    s = 0;
    for (int i = n - 1, j = n - 1; i >= 0; i--) {
        if (i == j) {
            j = (j + n - 1) % n;
            s += a[j] + 1;
        }
        while (i != j && a[j]) {
            j = (j + n - 1) % n;
            s += a[j] + 1;
        }
        pl[0][i] = j;
        cl[0][i] = s;
        if (i != 0) {
            s -= a[i - 1] + 1;
        }
    }
    for (int j = 1; j < 20; j++) for (int i = 0; i < n; i++) {
        cl[j][i] = cl[j - 1][i] + cl[j - 1][pl[j - 1][i]];
        cr[j][i] = cr[j - 1][i] + cr[j - 1][pr[j - 1][i]];
        pl[j][i] = pl[j - 1][pl[j - 1][i]];
        pr[j][i] = pr[j - 1][pr[j - 1][i]];
    }
    for (int i = 0; i < k; i++) {
        cin >> b[i];
        b[i]--;
    }
    
    sort(b, b + k);

    ll L = 0, R = 2e10;
    while (L < R) {
        ll M = (L + R) / 2;
        int sz = 0;
        for (int i = 0; i < k; i++) {
            ll x = M, y = M, p = b[i], q = b[i];
            int s = 0, t = 0;
            for (int j = 19; j >= 0; j--) {
                if (cl[j][p] <= x) {
                    x -= cl[j][p];
                    p = pl[j][p];
                    s += 1 << j;
                }
                if (cr[j][q] <= y) {
                    y -= cr[j][q];
                    q = pr[j][q];
                    t += 1 << j;
                }
            }
            // cout << M << ' ' << b[i] << ' ' << p << ' ' << q << ' ' << s << ' ' << t << '\n';
            if (s + t >= n - m - 1) {
                continue;
            }
            while (p > q) {
                q += n;
            }
            tmp[sz++] = { p, q };
        }
        if (sz == 0) {
            R = M;
            continue;
        }
        /* cout << M << "!\n";
        for (int i = 0; i < sz; i++) {
            cout << tmp[i].first << ' ' << tmp[i].second << '\n';
        } */

        int tz = 0;
        for (int i = 0; i < sz; i++) {
            if (i && tmp[i].first < tmp[i - 1].first) {
                tmp[i].first += n;
                tmp[i].second += n;
            }
            while (tz && c[tz - 1].second >= tmp[i].second) {
                --tz;
            }
            c[tz++] = tmp[i];
        }

        // check if ans = 1;
        for (int i = 0; i < 3 * n; i++) psum[i] = 0;
        for (int i = 0; i < tz; i++) {
            psum[c[i].first]++;
            psum[c[i].second + 1]--;
        }
        bool f = false;
        for (int i = 1; i < 3 * n; i++) {
            psum[i] += psum[i - 1];
        }
        for (int i = n; i < 3 * n; i++) {
            psum[i % n] += psum[i];
        }
        for (int i = 0; i < n; i++) {
            if (psum[i] == tz) f = true;
        }
        if (f) {
            R = M;
            continue;
        }
        
        sz = tz;
        for (int i = 0; i < tz; i++) {
            if (c[i].second >= c[0].first + n) {
                sz = i;
                break;
            }
        }

        /* cout << M << "!\n";
        for (int i = 0; i < tz; i++) {
            cout << c[i].first << ' ' << c[i].second << '\n';
        } */

        int lz = 3 * n + 1, rz = -1, ans = 0;
        for (int i = 0; i < sz; i++) {
            if (rz < c[i].first) {
                rz = c[i].second;
                ++ans;
            }
        }
        for (int i = sz - 1; i >= 0; i--) {
            if (lz > c[i].second) {
                lz = c[i].first;
            }
        }

        if (ans == 1) {
            ans += 1;
        }
        else {
            f = true;
            for (int i = sz; i < tz; i++) {
                if (c[i].first > rz && c[i].second - n < lz) {
                    f = false;
                }
            }
            if (!f) ans += 1;
        }

        if (ans <= p) R = M;
        else L = M + 1;        
    }
    cout << L;
}