#include <bits/stdc++.h>
using namespace std;
#ifndef ONLINE_JUDGE
	#include <boost/multiprecision/cpp_int.hpp>
	#include <boost/multiprecision/cpp_dec_float.hpp>
	using bll = boost::multiprecision::cpp_int;
	using bdouble = boost::multiprecision::cpp_dec_float_100;
#endif
#ifdef LOCAL_DEV
	void debug_impl() { std::cerr << std::endl; }
	template<typename Head, typename... Tail> void debug_impl(Head head, Tail... tail) { std::cerr << " " << head << (sizeof...(tail) ? "," : ""); debug_impl(tail...); }
	#define debug(...) { std::cerr << std::boolalpha << "(" << #__VA_ARGS__ << ") ="; debug_impl(__VA_ARGS__); std::cerr << std::noboolalpha; }
#else
	#define debug(...) {}
#endif
#ifdef LOCAL_TEST
	#define BOOST_STACKTRACE_USE_ADDR2LINE
	#define BOOST_STACKTRACE_ADDR2LINE_LOCATION /usr/local/opt/binutils/bin/addr2line
	#define _GNU_SOURCE
	#include <boost/stacktrace.hpp>
	namespace std {
		template<typename T> class dvector : public std::vector<T> {
		public:
			dvector() : std::vector<T>() {}
			explicit dvector(size_t n, const T& value = T()) : std::vector<T>(n, value) {}
			dvector(const std::vector<T>& v) : std::vector<T>(v) {}
			dvector(const std::initializer_list<T> il) : std::vector<T>(il) {}
			dvector(const typename std::vector<T>::iterator first, const typename std::vector<T>::iterator last) : std::vector<T>(first, last) {}
			dvector(const std::string::iterator first, const std::string::iterator last) : std::vector<T>(first, last) {}
			T& operator[](size_t n) {
				try { return this->at(n); } catch (const std::exception& e) {
					std::cerr << boost::stacktrace::stacktrace() << std::endl; return this->at(n);
				}
			}
			const T& operator[](size_t n) const {
				try { return this->at(n); } catch (const std::exception& e) {
					std::cerr << boost::stacktrace::stacktrace() << std::endl; return this->at(n);
				}
			}
		};
	}
	class dbool {
	private:
		bool boolvalue;
	public:
		dbool() : boolvalue(false) {}
		dbool(bool b) : boolvalue(b) {}
		dbool(const dbool &b) : boolvalue(b.boolvalue) {}
		operator bool&() { return boolvalue; }
		operator const bool&() const { return boolvalue; }
	};
	template<typename T> std::ostream& operator<<(std::ostream& s, const dvector<T>& v) {
		for (int i = 0, len = v.size(); i < len; ++i){ s << v[i]; if (i < len - 1) s << "\t"; } return s; }
	template<typename T> std::ostream& operator<<(std::ostream& s, const dvector< dvector<T> >& vv) {
		for (int i = 0, len = vv.size(); i < len; ++i){ s << vv[i] << std::endl; } return s; }
	template<typename T> std::ostream& operator<<(std::ostream& s, const std::set<T>& se) {
		s << "{ "; for (auto itr = se.begin(); itr != se.end(); ++itr){ s << (*itr) << "\t"; } s << "}"; return s; }
	template<typename T> std::ostream& operator<<(std::ostream& s, const std::multiset<T>& se) {
		s << "{ "; for (auto itr = se.begin(); itr != se.end(); ++itr){ s << (*itr) << "\t"; } s << "}"; return s; }
	template<typename T1, typename T2> std::ostream& operator<<(std::ostream& s, const std::map<T1, T2>& m) {
		s << "{" << std::endl; for (auto itr = m.begin(); itr != m.end(); ++itr){ s << "\t" << (*itr).first << " : " << (*itr).second << std::endl; } s << "}"; return s; }
	template<typename T1, typename T2> std::ostream& operator<<(std::ostream& s, const std::pair<T1, T2>& p) { 
		return s << "(" << p.first << ", " << p.second << ")"; }
	#define vector dvector
	#define bool dbool
	class SIGFPE_exception : std::exception {};
	class SIGSEGV_exception : std::exception {};
	void catch_SIGFPE(int e) { std::cerr << boost::stacktrace::stacktrace() << std::endl; throw SIGFPE_exception();	}
	void catch_SIGSEGV(int e) { std::cerr << boost::stacktrace::stacktrace() << std::endl; throw SIGSEGV_exception(); }
	signed convertedmain();
	signed main() { signal(SIGFPE, catch_SIGFPE); signal(SIGSEGV, catch_SIGSEGV); return convertedmain(); }
	#define main() convertedmain()
#endif
//#define int long long
using ll = long long;
//constexpr int INF = 1e9;//INT_MAX=(1<<31)-1=2147483647
constexpr ll INF = (ll)1e18;//(1LL<<63)-1=9223372036854775807
constexpr ll MOD = (ll)1e9 + 7;
constexpr double EPS = 1e-9;
constexpr ll dx[4] = {1LL, 0LL, -1LL, 0LL};
constexpr ll dy[4] = {0LL, 1LL, 0LL, -1LL};
constexpr ll dx8[8] = {1LL, 0LL, -1LL, 0LL, 1LL, 1LL, -1LL, -1LL};
constexpr ll dy8[8] = {0LL, 1LL, 0LL, -1LL, 1LL, -1LL, 1LL, -1LL};
#define rep(i, n)   for(ll i=0, i##_length=(n); i< i##_length; ++i)
#define repeq(i, n) for(ll i=1, i##_length=(n); i<=i##_length; ++i)
#define rrep(i, n)   for(ll i=(n)-1; i>=0; --i)
#define rrepeq(i, n) for(ll i=(n)  ; i>=1; --i)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
void p() { std::cout << '\n'; }
template<typename Head, typename... Tail> void p(Head head, Tail... tail) { std::cout << head << (sizeof...(tail) ? " " : ""); p(tail...); }
template<typename T> inline void pv(std::vector<T> &v) { for(ll i=0, N=v.size(); i<N; i++) std::cout << v[i] << " \n"[i==N-1]; }
template<typename T> inline T gcd(T a, T b) { return b ? gcd(b,a%b) : a; }
template<typename T> inline T lcm(T a, T b) { return a / gcd(a,  b) * b; }
template<typename T> inline bool chmax(T &a, T b) { return a < b && (a = b, true); }
template<typename T> inline bool chmin(T &a, T b) { return a > b && (a = b, true); }
template<typename T> inline void uniq(std::vector<T> &v) { v.erase(unique(v.begin(), v.end()), v.end()); }

/*-----8<-----template-----8<-----*/

ll merge(vector<ll> &a, ll left, ll mid, ll right){
	ll i,j,k;
	ll count = 0;
	ll n1 = mid-left;
	ll n2 = right-mid;
	vector<ll> L(n1+1, 0), R(n2+1, 0);
	for(i=0; i<n1; i++) L[i] = a[left+i];
	for(i=0; i<n2; i++) R[i] = a[mid+i];
	L[n1] = R[n2] = INF;
	i=j=0;
	for(k=left; k<right; k++){
		if(L[i] <= R[j]) {
			a[k] = L[i];
			i++;
		} else {
			a[k] = R[j];
			j++;
			count += n1-i; // = mid+j-k-1
		}
	} 
	return count;
}

ll mergesort(vector<ll> &a, ll left, ll right){
	if(left+1 < right) {
		ll mid = (left+right)/2;
		ll v1 = mergesort(a, left, mid);
		ll v2 = mergesort(a, mid, right);
		ll v3 = merge(a, left, mid, right);
		return v1+v2+v3;
	} else {
		return 0;
	}
}


// (0..n-1)のn個の要素について、nCkの組み合わせに対して関数fを適用する
template<typename Function> void foreach_comb(ll n, ll k, Function f) {
	vector<ll> indexes(k);
	auto recursive_comb = [&](auto&& recursive_comb, vector<ll> &indexes, ll s, ll rest, Function& f){
		if (rest == 0) {
			f(indexes);
		} else {
			if (s < 0) return;
			recursive_comb(recursive_comb, indexes, s - 1, rest, f);
			indexes[rest - 1] = s;
			recursive_comb(recursive_comb, indexes, s - 1, rest - 1, f);
		}
	};
	recursive_comb(recursive_comb, indexes, n - 1, k, f);
}



/*-----8<-----library-----8<-----*/

constexpr ll N_MAX = 18;
constexpr ll A_I_MAX = 50;
constexpr ll B_I_MAX = 50;

ll N;
vector<ll> A;
vector<ll> B;

void solve() {
	scanf("%lld", &N);
	A.assign(N, 0);
	rep(i, N) { scanf("%lld", &A[i]); }
	B.assign(N, 0);
	rep(i, N) { scanf("%lld", &B[i]); }
	
	if([&]{
		rep(i,N-1){
			if(A[i]>A[i+1])return false;
		}
		return true;
	}()){
		p(0);return;
	}

	//dp[bit][i] = bitが立っているカードは左詰めで整列済み、整列済みの最後の値はi
	vector<vector<ll>> dp((1LL<<N), vector<ll>(51, INF));
	dp[0][0]=0;

	for (ll bit = 0, size = (1LL<<N); bit < size; bit++) {
		ll c=__builtin_popcount(bit);
		vector<pair<ll,ll>> nokori; //{初期のindex, 現bitでのindex}
		rep(i, N) {
			if (!(bit & (1LL<<i))) {
				//まだ整列されていない
				nokori.push_back({i,c});
				c++;
			}
		}
		for(pair<ll,ll> pr:nokori){
			//prを整列済み部分(bit)の末尾(__builtin_popcount(bit)番目)にくっつけようとしている
			ll dif = abs(pr.first-__builtin_popcount(bit));
			ll val = dif%2==0 ? A[pr.first] : B[pr.first];
			
			ll bitafter=bit|(1LL<<pr.first);
			ll swaptimes=pr.second-__builtin_popcount(bit);
			for(ll i=0;i<=val;i++){
				chmin(dp[bitafter][val], dp[bit][i]+swaptimes);
			}
		}
	}
	debug(dp);
	ll ans = INF;
	rep(i,dp[0].size()){
		chmin(ans,dp[(1<<N)-1][i]);
	}
	if(ans==INF){
		p(-1);return;
	}
	printf("%lld\n", ans);
	
}

// https://atcoder.jp/contests/keyence2020/tasks/keyence2020_d
signed main() {
	solve();
	return 0;
}


Measured memory_bytes: 112896