bunnies

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Scanner;

public class bunnies {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        int T = in.nextInt();

        for (int t = 1; t <= T; t++) {
            int n = in.nextInt();
            int[] tmps = new int[n];
            int[] hums = new int[n];

            HashMap<Integer, ArrayList<Integer>> Phums = new HashMap<Integer, ArrayList<Integer>>();
            HashMap<Integer, ArrayList<Integer>> Nhums = new HashMap<Integer, ArrayList<Integer>>();

            for (int i = 0; i < n; i++) {
                tmps[i] = in.nextInt();
            }

            for (int i = 0; i < n; i++) {
                hums[i] = in.nextInt();
            }

            for (int i = 0; i < n; i++) {
                int pos = tmps[i] + hums[i];
                int neg = tmps[i] - hums[i];

                if (!Phums.containsKey(pos)) {
                    Phums.put(pos, new ArrayList<Integer>());
                }
                Phums.get(pos).add(i);

                if (!Nhums.containsKey(neg)) {
                    Nhums.put(neg, new ArrayList<Integer>());
                }
                Nhums.get(neg).add(i);
            }

            ArrayList<Integer> q = new ArrayList<Integer>();
            boolean[] visited = new boolean[n];

            q.add(0);
            visited[0] = true;

            int step;
            for (step = 0; q.size() > 0 && !visited[n - 1]; step++) {
                ArrayList<Integer> nq = new ArrayList<Integer>();

                while (q.size() > 0) {
                    int ind = q.remove(q.size() - 1);

                    int pos = tmps[ind] + hums[ind];
                    int neg = tmps[ind] - hums[ind];

                    if (Phums.containsKey(pos)) {
                        for (int i : Phums.get(pos)) {
                            if (!visited[i]) {
                                visited[i] = true;
                                nq.add(i);
                            }
                        }
                        Phums.remove(pos);
                    }

                    if (Nhums.containsKey(neg)) {
                        for (int i : Nhums.get(neg)) {
                            if (!visited[i]) {
                                visited[i] = true;
                                nq.add(i);
                            }
                        }
                        Nhums.remove(neg);
                    }
                }

                q = nq;
            }

            if (!visited[n - 1]) {
                step = -1;
            }
            System.out.println("Field #" + t + ": " + step + "\n");
        }

        in.close();
    }

    public static void debug(Object o) {
        System.out.println("\tDEBUG: " + o.toString().replaceAll("\n", "\n\tDEBUG: "));
    }
}