#include <bits/stdc++.h>
using namespace std;
using lint = long long int;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((lint)(x).size())
#define POW2(n) (1LL << (n))
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template<typename T> istream &operator>>(istream &is, vector<T> &vec){ for (auto &v : vec) is >> v; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const deque<T> &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename T> void ndarray(vector<T> &vec, int len) { vec.resize(len); }
template<typename T, typename... Args> void ndarray(vector<T> &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); }
template<typename T> bool mmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template<typename T> bool mmin(T &m, const T q) { if (q < m) {m = q; return true;} else return false; }
template<typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l.second + r.second); }
template<typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l.second - r.second); }
#define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl;

constexpr int INF = 1e8;

lint next_combination(lint comb)
{
    lint x = comb & -comb, y = comb + x;
    return ((comb & ~y) / x >> 1) | y;
}


int main()
{
    int N;
    cin >> N;
    vector<int> A(N), B(N);
    cin >> A >> B;
    for (int j = 1; j < N; j += 2) swap(A[j], B[j]);

    A.push_back(-INF);
    B.push_back(-INF);

    vector<vector<int>> DP(N + 1, vector<int>(1 << N, INF));
    DP[N][0] = 0;

    REP(n, N)
    {
        int S = (1 << n) - 1;
        while (S < (1 << N))
        {
            REP(j, N + 1)
            {
                if (DP[j][S] < INF)
                {
                    int lastv = (n % 2 ? A[j] : B[j]);
                    REP(nxt, N) if (!((S >> nxt) & 1))
                    {
                        int nxtv = (n % 2 ? B[nxt] : A[nxt]);
                        if (nxtv >= lastv)
                        {
                            int cost = nxt - __builtin_popcount(S & ((1 << nxt) - 1));
                            mmin(DP[nxt][S + (1 << nxt)], DP[j][S] + cost);
                        }
                    }
                }
            }
            if (S == 0) break;
            S = next_combination(S);
        }
    }

    int ret = INF;
    REP(i, N) mmin(ret, DP[i].back());
    if (ret == INF) puts("-1");
    else {
        // assert(ret % 2 == 0);
        cout << ret << endl;
    }
}


Measured memory_bytes: 20864