/*CODED BY mahmudulsakib2019
  DATE:-06/3/2024;TIME:-07:39 pm
  BANGALDESH , SYLHET*/

#include <iostream>
#include <vector>
using namespace std;

int main() {
    int T;
    cin >> T;
    while (T--) {
        int T1, T2, N;
        cin >> T1 >> T2 >> N;
        vector<int> A(N), B(N);
        for (int i = 0; i < N; ++i) cin >> A[i];
        for (int i = 0; i < N; ++i) cin >> B[i];
        int minTrain = min(T1, T2);
        int minTime = 1e9;
        for (int i = 0; i < N; ++i) {
            if (B[i] > minTrain) {
                minTime = min(minTime, max(A[i], N - 1 - A[i]));
            }
        }
        if (minTime == 1e9) {
            cout << -1 << endl;
        } else {
            cout << minTime << endl;
        }
    }
    return 0;
}