#include "robots.h"
#include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int) (x).size()

int putaway(int A, int B, int T, int X[], int Y[], int W[], int S[]) {
    vector<int> ord_weak(A), ord_small(B);
    iota(all(ord_weak), 0); iota(all(ord_small), 0);
    sort(all(ord_weak), [&](int p1, int p2) {
        return X[p1] < X[p2];
    });
    sort(all(ord_small), [&](int p1, int p2) {
        return Y[p1] < Y[p2];
    });

    vector<int> toys_order(T), tow(T);
    iota(all(toys_order), 0); iota(all(tow), 0);
    sort(all(tow), [&](int p1, int p2) {return W[p1] < W[p2];});
    sort(all(toys_order), [&](int p1, int p2) {
        return S[p1] < S[p2];
    });

    int L = 0, R = T + 1;
    while (R - L > 1) {
        int M = (L + R) / 2;
        //cout << M << '\n';
        int ci = 0;
        vector<int> used(T, 0);
        set<pair<int, int>> st;
        for (int i = 0; i < sz(ord_small); i++) {
            while (ci < T && S[toys_order[ci]] < Y[ord_small[i]]) {
                st.insert({-W[toys_order[ci]], toys_order[ci]});
                //cout << "add " << toys_order[ci] << '\n';
                ci++;
            }
            int cur = M;
            while (cur && !st.empty()) {
                auto it = st.begin();
                used[(*it).second] = 1;
                //cout << "delete " << (*it).second << '\n';
                st.erase(it); cur--;
            }
        }
        int cb = 0;
        int siiu = 0;
        for (int i = 0; i < sz(ord_weak); i++) {
            while (siiu < T && W[tow[siiu]] < X[ord_weak[i]]) {
                siiu++;
                cb += !used[siiu - 1];
            }
            cb = max(0, cb - M);
        }
        while (siiu < T) {
            cb += !used[siiu];
            siiu++;
        }
        if (cb) L = M;
        else R = M;
    }
    return (R == T + 1 ? -1 : R);
}   

#ifdef LOCAL 
    signed main() {
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
        int a, b, t; cin >> a >> b >> t;
        int x[a], y[b], s[t], w[t];
        for (int i = 0; i < a; i++) cin >> x[i];
        for (int i = 0; i < b; i++) cin >> y[i];
        for (int i = 0; i < t; i++) cin >> w[i] >> s[i];
        cout << putaway(a, b, t, x, y, w, s) << '\n';
    }
#endif