#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef double ld;
//#define ll __int128
//#define int ll
//#define char ll
//#define double ld
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef pair<int, int> pii;
typedef pair<pii, pii> piii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for(int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cout << (#x) << " = " << (x) << endl;

#ifdef MAX_HOME
#define cerr cout
#else
#define cerr if (false) cerr
#endif

const double PI = 2 * acos(0.0);
//#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";


template<class T0, class T1>
inline ostream &operator<<(ostream &out, pair<T0, T1> &a) {
    return out << "{" << a.first << ", " << a.second << "}";
}

template<class T0, class T1>
inline istream &operator>>(istream &in, pair<T0, T1> &a) {
    return in >> a.first >> a.second;
}

template<class T0, class T1, class T2>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << "}";
}

template<class T0, class T1, class T2, class T3>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2, T3> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ", " << get<3>(a) << "}";
}

template<class T>
inline ostream &operator<<(ostream &out, vector<T> &a) {
    out << "[";
    fori (i, a.size())out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
    return out;
}


void smain();


signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
#ifdef MAX_HOME
    freopen("input.txt", "r", stdin);
    clock_t start = clock();
#endif
    cout << setprecision(12) << fixed;
    smain();
#ifdef MAX_HOME
    cout << "\n\nTOTAL EXECUTION TIME: " << float(clock() - start) / CLOCKS_PER_SEC << endl;
#endif
    return 0;
}

const int N = 18;

int a[N], b[N];

void smain() {

    int n;
    cin >> n;
    fori (i, n) {
        cin >> a[i];
    }
    fori (i, n) {
        cin >> b[i];
    }
    vi cnt(2, 0);
    fori (i, n) {
        cnt[i & 1]++;
    }
    int ans = -1;
    fori (mask, 1 << n) {
        vi cur(2, 0);
        vector<vector<pii>> res(2, vector<pii>());
        fori (i, n) {
            bool bt = (mask >> i) & 1;
            cur[bt ^ (i & 1)]++;
            if (bt) {
                res[bt ^ (i & 1)].push_back({b[i], i});
            } else {
                res[bt ^ (i & 1)].push_back({a[i], i});
            }
        }
        if (cur == cnt) {
            sort(ALL(res[0]));
            sort(ALL(res[1]));
            vector<pii> kek;
            for (int j = 0; j < max(res[0].size(), res[1].size()); ++j) {
                kek.push_back(res[0][j]);
                if (j < res[1].size())
                    kek.push_back(res[1][j]);
            }
            bool srted = true;
            fori (i, n - 1) {
                if (kek[i].first > kek[i + 1].first)
                    srted = false;
            }
            if (srted) {
                int cans = 0;
                fori (i, n) {
                    fori (j, i) {
                        if (kek[j].second > kek[i].second) {
                            ++cans;
                        }
                    }
                }
                if (ans == -1)
                    ans = cans;
                inmin(ans, cans);
            }
        }
    }
    cout << ans;
}

Measured memory_bytes: 3620