using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;

namespace AtCoder
{
	public class Program
	{
		static void Main()
		{
			var cin = new Scanner();
			int n = cin.Int();
			int[] a = cin.ArrayInt(n);
			int[] b = cin.ArrayInt(n);

			long ans = long.MaxValue;
			for (int k = 0; k < 1 << n; k++) {
				var q = new PriorityQueue<PriorityPair<int, Card>>(n, true);
				for (int i = 0; i < n; i++) {
					bool isBlue = (k & (1 << i)) != 0;
					q.Enqueue(new PriorityPair<int, Card>(
						(isBlue ? b[i] : a[i]) * 100 + i,
						new Card(i, isBlue)));
				}

				bool ok = true;
				var indexes = new List<int>(n);
				while (q.Count > 0) {
					int number = q.Top.Priority / 100;
					var first = new PriorityQueue<int>(n / 2, true);
					var second = new PriorityQueue<int>(n / 2, true);
					while (q.Count > 0 && q.Top.Priority / 100 == number) {
						var next = q.Dequeue();
						if (Math.Abs(indexes.Count - next.Item.Index) % 2 == 0) {
							if (next.Item.IsBlue) {
								second.Enqueue(next.Item.Index);
							} else {
								first.Enqueue(next.Item.Index);
							}
						} else {
							if (next.Item.IsBlue) {
								first.Enqueue(next.Item.Index);
							} else {
								second.Enqueue(next.Item.Index);
							}
						}
					}

					bool ok2 = true;
					while (first.Count > 0 || second.Count > 0) {
						if (first.Count == 0) {
							ok2 = false;
							break;
						}

						indexes.Add(first.Dequeue());

						if (second.Count == 0) {
							if (first.Count > 0) {
								ok2 = false;
							}

							break;
						}

						indexes.Add(second.Dequeue());
					}

					if (ok2 == false) {
						ok = false;
						break;
					}
				}

				if (ok == false) {
					continue;
				}

				int cnt = 0;
				for (int i = 0; i < n - 1; i++) {
					for (int j = i + 1; j < n; j++) {
						if (indexes[j] < indexes[i]) {
							++cnt;
						}
					}
				}

				ans = Math.Min(ans, cnt);
			}

			if (ans != long.MaxValue) {
				Console.WriteLine(ans);
			} else {
				Console.WriteLine(-1);
			}
		}
	}

	public struct Card
	{
		public int Index;
		public bool IsBlue;
		public Card(int index, bool isBlue)
		{
			Index = index;
			IsBlue = isBlue;
		}
	}

	public struct PriorityPair<T, U> : IComparable<PriorityPair<T, U>>
			where T : IComparable<T>
	{
		public T Priority { get; set; }
		public U Item { get; set; }

		public PriorityPair(T priority, U item)
		{
			Priority = priority;
			Item = item;
		}

		public int CompareTo(PriorityPair<T, U> target)
			=> Priority.CompareTo(target.Priority);

		public override string ToString()
			=> $"{Priority} {Item}";
	}

	public class PriorityQueue<T> where T : IComparable<T>
	{
		private readonly int reverseFactor_;
		private T[] heap_;

		public T Top => heap_[0];
		public int Count { get; private set; } = 0;

		public PriorityQueue(bool reverses = false)
			: this(1024, reverses) { }

		public PriorityQueue(
			int capacity,
			bool reverses = false)
		{
			heap_ = new T[capacity > 0 ? capacity : 1];
			reverseFactor_ = reverses ? -1 : 1;
		}

		public void Enqueue(T item)
		{
			if (heap_.Length == Count) {
				Extend(heap_.Length * 2);
			}

			heap_[Count] = item;
			++Count;

			int c = Count - 1;
			while (c > 0) {
				int p = (c - 1) >> 1;
				if (Compare(heap_[p], item) < 0) {
					heap_[c] = heap_[p];
					c = p;
				} else {
					break;
				}
			}

			heap_[c] = item;
		}

		public T Dequeue()
		{
			T ret = heap_[0];
			int n = Count - 1;

			var item = heap_[n];
			int p = 0;
			int c = (p << 1) + 1;
			while (c < n) {
				if (c != n - 1 && Compare(heap_[c + 1], heap_[c]) > 0) {
					++c;
				}

				if (Compare(item, heap_[c]) < 0) {
					heap_[p] = heap_[c];
					p = c;
					c = (p << 1) + 1;
				} else {
					break;
				}
			}

			heap_[p] = item;
			Count--;

			return ret;
		}

		public void Clear() => Count = 0;

		[MethodImpl(MethodImplOptions.AggressiveInlining)]
		private int Compare(T x, T y)
			=> x.CompareTo(y) * reverseFactor_;

		[MethodImpl(MethodImplOptions.AggressiveInlining)]
		private void Extend(int newSize)
		{
			var newHeap = new T[newSize];
			heap_.CopyTo(newHeap, 0);
			heap_ = newHeap;
		}
	}

	public class HashMap<TKey, TValue> : Dictionary<TKey, TValue>
	{
		private readonly Func<TKey, TValue> initialzier_;
		public HashMap(Func<TKey, TValue> initialzier)
			: base()
		{
			initialzier_ = initialzier;
		}

		public HashMap(Func<TKey, TValue> initialzier, int capacity)
			: base(capacity)
		{
			initialzier_ = initialzier;
		}

		new public TValue this[TKey key]
		{
			get
			{
				if (ContainsKey(key) == false) {
					base[key] = initialzier_(key);
				}

				return base[key];
			}

			set { base[key] = value; }
		}
	}

	public static class Helper
	{
		public static void UpdateMin<T>(ref T target, T value) where T : IComparable<T>
			=> target = target.CompareTo(value) > 0 ? value : target;

		public static void UpdateMin<T>(ref T target, T value, Action<T> onUpdated) where T : IComparable<T>
		{
			if (target.CompareTo(value) > 0) {
				target = value;
				onUpdated(value);
			}
		}

		public static void UpdateMax<T>(ref T target, T value) where T : IComparable<T>
			=> target = target.CompareTo(value) < 0 ? value : target;
		public static void UpdateMax<T>(ref T target, T value, Action<T> onUpdated) where T : IComparable<T>
		{
			if (target.CompareTo(value) < 0) {
				target = value;
				onUpdated(value);
			}
		}

		public static T[] Array<T>(int n, Func<int, T> init)
			=> Enumerable.Range(0, n).Select(x => init(x)).ToArray();
		public static List<T> List<T>(int n, Func<int, T> init)
			=> Enumerable.Range(0, n).Select(x => init(x)).ToList();
		public static T[,] Array2<T>(int n, int m, T init)
		{
			var array = new T[n, m];
			for (int i = 0; i < n; i++) {
				for (int j = 0; j < m; j++) {
					array[i, j] = init;
				}
			}

			return array;
		}

		public static T[,] Array2<T>(int n, int m, Func<int, int, T> initializer)
		{
			var array = new T[n, m];
			for (int i = 0; i < n; i++) {
				for (int j = 0; j < m; j++) {
					array[i, j] = initializer(i, j);
				}
			}

			return array;
		}

		public static T[,,] Array3<T>(int n1, int n2, int n3, T init)
		{
			var array = new T[n1, n2, n3];
			for (int i1 = 0; i1 < n1; i1++) {
				for (int i2 = 0; i2 < n2; i2++) {
					for (int i3 = 0; i3 < n3; i3++) {
						array[i1, i2, i3] = init;
					}
				}
			}

			return array;
		}

		private static readonly int[] delta4_ = { 1, 0, -1, 0, 1 };
		public static void DoAt4(int i, int j, int imax, int jmax, Action<int, int> action)
		{
			for (int n = 0; n < 4; n++) {
				int ii = i + delta4_[n];
				int jj = j + delta4_[n + 1];
				if ((uint)ii < (uint)imax && (uint)jj < (uint)jmax) {
					action(ii, jj);
				}
			}
		}
	}

	public class Scanner
	{
		private readonly char[] delimiter_ = new char[] { ' ' };
		private readonly string filePath_;
		private readonly Func<string> reader_;
		private string[] buf_;
		private int index_;

		public Scanner(string file = "")
		{
			if (string.IsNullOrWhiteSpace(file)) {
				reader_ = Console.ReadLine;
			} else {
				filePath_ = file;
				var fs = new StreamReader(file);
				reader_ = fs.ReadLine;
			}
			buf_ = new string[0];
			index_ = 0;
		}

		public string Next()
		{
			if (index_ < buf_.Length) {
				return buf_[index_++];
			}

			string st = reader_();
			while (st == "") {
				st = reader_();
			}

			buf_ = st.Split(delimiter_, StringSplitOptions.RemoveEmptyEntries);
			if (buf_.Length == 0) {
				return Next();
			}

			index_ = 0;
			return buf_[index_++];
		}

		public int Int() => int.Parse(Next());
		public long Long() => long.Parse(Next());
		public double Double() => double.Parse(Next());

		public int[] ArrayInt(int N, int add = 0)
		{
			int[] Array = new int[N];
			for (int i = 0; i < N; i++) {
				Array[i] = Int() + add;
			}
			return Array;
		}

		public long[] ArrayLong(int N, long add = 0)
		{
			long[] Array = new long[N];
			for (int i = 0; i < N; i++) {
				Array[i] = Long() + add;
			}
			return Array;
		}

		public double[] ArrayDouble(int N, double add = 0)
		{
			double[] Array = new double[N];
			for (int i = 0; i < N; i++) {
				Array[i] = Double() + add;
			}
			return Array;
		}

		public void Save(string text)
		{
			if (string.IsNullOrWhiteSpace(filePath_)) {
				return;
			}

			File.WriteAllText(filePath_ + "_output.txt", text);
		}
	}
}

Measured memory_bytes: 17440