#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;

const int N = 202020;
typedef long long ll;

int n, m, k, p, t[N], d[N], l[N], r[N];
ll pl[20][N], pr[20][N], cl[20][N], cr[20][N];
pair<int, int> V[2 * N], stk[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 >> t[x - 1];
    }

    for (int i = 0; i < k; i++) {
        cin >> d[i];
        d[i]--;
    }
    sort(d, d + k);

    ll s = 0;
    for (int i = 0, r = 0; i < n; i++) {
        if (i != 0) s -= t[i] + 1;
        if (r == i) {
            r = (r + 1) % n;
            s += t[r] + 1;
        }
        while (r != i && t[r]) {
            r = (r + 1) % n;
            s += t[r] + 1;
        }
        cr[0][i] = s;
        pr[0][i] = r;
    }
    s = 0;
    for (int i = n - 1, l = n - 1; i >= 0; i--) {
        if (i != n - 1) s -= t[i] + 1;
        if (l == i) {
            l = (l + n - 1) % n;
            s += t[l] + 1;
        }
        while (l != i && t[l]) {
            l = (l + n - 1) % n;
            s += t[l] + 1;
        }
        cl[0][i] = s;
        pl[0][i] = l;
    }

    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]];
    }

    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, l = 0, r = 0;
            int p = d[i], q = d[i];
            for (int j = 19; j >= 0; j--) {
                if (cl[j][p] <= x) {
                    x -= cl[j][p];
                    p = pl[j][p];
                    l ^= 1 << j;
                }
                if (cr[j][q] <= y) {
                    y -= cr[j][q];
                    q = pr[j][q];
                    r ^= 1 << j;
                }
            }
            if (l + r >= n - 1) continue;
            V[sz++] = {p, q};
        }
        if (sz == 0) {
            R = M; continue;
        }
        // cout << M << "!\n";
        // for (auto [l, r] : V) {
        //     cout << l << ' '<< r << '\n';
        // }

        int x = 0;
        while (x < sz && V[x].first > V[x].second) {
            ++x;
        }
        for (int i = 0; i < x; i++) {
            V[sz + i] = V[i];
        }
        for (int i = 0; i < sz; i++) {
            swap(V[i], V[i + x]);
        }

        int tz = 0;
        for (int i = 0; i < sz; i++) {
            auto [l, r] = V[i];
            if (r < l) r += n;

            // cout << l << ' ' << r << "?\n";
            while (tz != 0 && stk[tz - 1].second >= r) {
                --tz;
            }
            stk[tz++] = {l, r};
        }
        int rend = -1, lend = n + 1;

        int ans = 0;
        for (int i = 0; i < tz; i++) {
            if (stk[i].second >= n) continue;
            if (rend < stk[i].first) {
                ++ans;
                rend = stk[i].second;
            }
        }
        for (int i = tz - 1; i >= 0; i--) {
            if (stk[i].second >= n) continue;
            if (lend > stk[i].second) {
                lend = stk[i].first;
            }
        }
        // cout << lend << ' ' << rend << "!!\n";

        if (lend == -1 || rend == -1) {
            ans = 1;
        }
        else if (ans == 1) {
            auto [a, b] = stk[0];
            auto [c, d] = stk[tz - 1];
            if (b < c) {
                ans = 2;
            }
        }
        else {
            bool f = true;
            for (int i = 0; i < tz; i++) {
                if (stk[i].second < n) continue;
                auto [r, l] = stk[i]; 
                l -= n;
                if (l < lend && r > rend) {
                    f = false;
                }
            }
            ans += (!f);
        }

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