/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author Gosu_Hiroo
 */

#include <iostream>
#include <fstream>

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#ifdef int
#define VI vector<long long>
#define V2I(v,size_1, size_2, value) vector<vector<long long>>v(size_1, vector<long long>(size_2, value))
#define V3I(v,size_1,size_2,size_3,value) vector<vector<vector<long long>>>v(size_1,vector<vector<long long>>(size_2,vector<long long>(size_3, value)))
#define G(g,size_1) vector<vector<long long>>g(size_1, vector<long long>())
#define SZ(x) ((long long)(x).size())
#define READ ({long long t;cin >> t;t;})
#define PII pair<long long, long long>
#else
#define VI vector<int>
#define V2I(v, size_1, size_2, value) vector<vector<int>>v(size_1, vector<int>(size_2, value))
#define V3I(v, size_1, size_2, size_3, value) vector<vector<vector<int>>>v(size_1,vector<vector<int>>(size_2,vector<int>(size_3, value)))
#define G(g, size_1) vector<vector<int>>g(size_1, vector<int>())
#define SZ(x) ((int)(x).size())
#define READ ({int t;cin >> t;t;})
#define PII pair<int, int>
#endif

#define V2(v, type, size_1, size_2, value) vector<vector<type>>v(size_1, vector<type>(size_2, value))
#define V3(v, type, size_1, size_2, size_3, value) vector<vector<vector<type>>>v(size_1,vector<vector<type>>(size_2,vector<type>(size_3, value)))

#define TR(container, it) \
        for (auto it = container.begin(); it != container.end(); it++)
#define IN(c, x) ((c).find(x) != (c).end())   //O(log n)
#define IN_L(c, x) (find((c).begin(),(c).end(),x) != (c).end()) //O(n)
#define FOR(i, _begin, _end) for (__typeof(_end) end = _end, begin = _begin,  i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1 - 2 * ((begin) > (end)))
#define REP(i, end) for (__typeof(end) i = 0, _len = (end); i < (_len); i += 1)
#define ALL(x) (x).begin(),(x).end()
#define F first
#define S second
#define y0 y3487465
#define y1 y8687969
#define j0 j1347829
#define j1 j234892
#define MOD(x, m) ((((x) % (m)) + (m)) % (m))
#define BIT(n) (1LL<<(n))
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
#define EB emplace_back
#define PB push_back
#define fcout cout << fixed << setprecision(12)
#define fcerr cerr << fixed << setprecision(12)
#define print(x) cout << (x) << endl
#define fprint(x) cout << fixed << setprecision(12) << (x) << endl
# define BYE(a) do { cout << (a) << endl; return ; } while (false)

#ifdef DEBUG
#define ERR(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); _err(cerr,_it, args); }
#define DBG(x) cerr << #x << " is " << x << endl;
#else
#define DBG(x) {};
#define ERR(args...) {};
#endif

void _err(std::ostream &cerr, istream_iterator<string> it) { cerr << endl; }

template<typename T, typename... Args>
void _err(std::ostream &cerr, istream_iterator<string> it, T a, Args... args) {
    cerr << *it << " = " << a << "  ";
    _err(cerr, ++it, args...);
}

const double pi = 2 * acos(.0);
const int inf = 0x3f3f3f3f;
const ll mod = (ll) (1e9) + 7;
//const ll mod = (ll) 998244353 ;
const double eps = 1e-10;

template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
    std::fill((T *) array, (T *) (array + N), val);
}


template<typename T>
ostream &operator<<(ostream &os, const vector<T> V) {
    os << "[";
    int cnt = 0;
    T curr;
    if (!V.empty()) {
        for (int i = 0; i < V.size() - 1; ++i) {
            if (V[i] == curr)cnt++;
            else cnt = 0;
            if (cnt == 4)os << "... ";
            if (cnt < 4)
                os << V[i] << " ";
            curr = V[i];
        }
        os << V.back();
    }
    os << "]";
    return os;
}

template<typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> P) {
    os << "(";
    os << P.first << "," << P.second;
    os << ")";
    return os;
}

template<typename T, typename U>
ostream &operator<<(ostream &os, const set<T, U> V) {
    os << "{";
    if (!V.empty()) {
        auto it = V.begin();
        for (int i = 0; i < V.size() - 1; ++i) {
            os << *it << " ";
            it++;
        }
        os << *it;
    }
    os << "}";
    return os;
}

template<typename K, typename H, typename P>
ostream &operator<<(ostream &os, const unordered_set<K, H, P> V) {
    os << "{";
    if (!V.empty()) {
        auto it = V.begin();
        for (int i = 0; i < V.size() - 1; ++i) {
            os << *it << " ";
            it++;
        }
        os << *it;
    }
    os << "}";
    return os;
}

template<typename K, typename C>
ostream &operator<<(ostream &os, const multiset<K, C> V) {
    os << "{";
    if (!V.empty()) {
        auto it = V.begin();
        for (int i = 0; i < V.size() - 1; ++i) {
            os << *it << " ";
            it++;
        }
        os << *it;
    }
    os << "}";
    return os;
}

template<typename K, typename T, typename C>
ostream &operator<<(ostream &os, const map<K, T, C> V) {
    os << "{";
    if (!V.empty()) {
        auto it = V.begin();
        for (int i = 0; i < V.size() - 1; ++i) {
            os << "(";
            os << it->first << "," << it->second;
            os << ") ";
            it++;
        }
        os << "(";
        os << it->first << "," << it->second;
        os << ")";
    }
    os << "}";
    return os;
}

template<typename K, typename T, typename C>
ostream &operator<<(ostream &os, const unordered_map<K, T, C> V) {
    os << "{";
    if (!V.empty()) {
        auto it = V.begin();
        for (int i = 0; i < V.size() - 1; ++i) {
            os << "(";
            os << it->first << "," << it->second;
            os << ") ";
            it++;
        }
        os << "(";
        os << it->first << "," << it->second;
        os << ")";
    }
    os << "}";
    return os;
}

template<typename T>
ostream &operator<<(ostream &os, const deque<T> V) {
    os << "[";
    if (!V.empty()) {
        for (int i = 0; i < V.size() - 1; ++i) {
            os << V[i] << "->";
        }
        if (!V.empty())os << V.back();
    }
    os << "]";
    return os;
};

template<typename T, typename Cont, typename Comp>
ostream &operator<<(ostream &os, const priority_queue<T, Cont, Comp> V) {
    priority_queue<T, Cont, Comp> _V = V;
    os << "[";
    if (!_V.empty()) {
        while (_V.size() > 1) {
            os << _V.top() << "->";
            _V.pop();
        }
        os << _V.top();
    }
    os << "]";
    return os;
};

template<class F>
struct y_combinator {
    F f; // the lambda will be stored here

    // a forwarding operator():
    template<class... Args>
    decltype(auto) operator()(Args &&... args) const {
        // we pass ourselves to f, then the arguments.
        // the lambda should take the first argument as `auto&& recurse` or similar.
        return f(*this, std::forward<Args>(args)...);
    }
};

// helper function that deduces the type of the lambda:
template<class F>
y_combinator<std::decay_t<F>> recursive(F &&f) {
    return {std::forward<F>(f)};
}

struct hash_pair {
    template<class T1, class T2>
    size_t operator()(const pair<T1, T2> &p) const {
        auto hash1 = hash<T1>{}(p.first);
        auto hash2 = hash<T2>{}(p.second);
        return hash1 ^ hash2;
    }

};

/*
struct X{
   int x,y,id;
   bool operator < (const X R)const{
       return id < R.id;
   }
   friend ostream& operator << (ostream& os,  X R){
       os << "(" << R.x << "," << R.y << "," << R.id << ")";
   }
   friend bool operator == (const X L,  const X R){
       return L.id == R.id;
   }
*/
template<class T>
void Chmod(T &a, const T &m) { a = MOD(a, m); }

template<class T>
bool Chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}

template<class T>
bool Chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return 1;
    }
    return 0;
}

//256MB = 2^29(~5.3*10^8)*sizeof(int)
//#define int ll //2^31=2.15*10^9, 2^63=9.22*10^18
struct Card {
    int c0, c1;

    bool operator<(const Card R) const {

    }

    bool operator==(const Card R) const {

    }

    friend ostream &operator<<(ostream &os, const Card R) {
        {


        }

    };
};

class DSwapAndFlip {
public:

    void solve(std::istream &cin, std::ostream &cout, std::ostream &cerr) {
        int N;
        cin >> N;
        int ans = 1e9;
        vector<Card> cards(N);
        REP(i, N)cin >> cards[i].c0;
        REP(i, N)cin >> cards[i].c1;
        vector<PII > order;
//        vector<int> order(55);
//        G(order, 55);

        auto ok = [&](int mask) {
            int sum = 0;
            vector<int> pairing(N,-1);
            ERR(mask)
            REP(i,N){
                int num;
                if(mask & BIT(i))num = cards[i].c1;else num = cards[i].c0;
                REP(j,N){
                    ERR(i,j,num,order[j].F)
                    ERR(num == order[j].F )
                    ERR((abs(i-j)%2 ), ( mask & BIT(i)))
                    ERR( pairing[j])
                    if(num == order[j].F && ((abs(i-j)%2 )== !!( mask & BIT(i))) && pairing[j] == -1){
                        ERR(i,j)
                        pairing[j] = i;
                        break;
                    }
                }
            }
            ERR(pairing)
            REP(j,N)if(pairing[j] == -1)return -1;
//
//            REP(i, N) {
//                if (abs(order[i].S - i) % 2) { if (order[i].F != cards[order[i].S].c1){ERR(i,order[i].F,cards[order[i].S].c1);return -1;} }
//                else { if (order[i].F != cards[order[i].S].c0){ERR(i,order[i].F,cards[order[i].S].c0);return -1;} }
//            }
            REP(i,N-1)FOR(j,i+1,N)if(pairing[i] > pairing[j])sum ++;
            return sum;
        };
        REP(mask, BIT(N)) {
            order.clear();

            REP(i, N) {
                if (mask & BIT(i))
//                    order[cards[i].c1].EB(i);
                    order.PB({cards[i].c1, i});
                else order.PB({cards[i].c0, i});
            }
            sort(ALL(order));

            ERR(order)
            int t = ok(mask);
            ERR(t)
            if (~t) {
                Chmin(ans, t);
            }
        }
        print((ans > 1e8) ? -1 : ans);
    }


};


#undef int
int main() {

	DSwapAndFlip solver;
	std::istream& in(std::cin);
	std::ostream& out(std::cout);
    std::ostringstream err;
	in.tie(0); ios::sync_with_stdio(0);
//	solver.solve(in, out);
    solver.solve(in, out,err);
	return 0;
}


Measured memory_bytes: 256