/* Aa^~ kokoro ga pyonpyon suru n jaa^~
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*/

#include <bits/stdc++.h>
using namespace std;

using VI = vector<int>;
using VVI = vector<VI>;
using PII = pair<int, int>;
using LL = long long;
using VL = vector<LL>;
using VVL = vector<VL>;
using PLL = pair<LL, LL>;
using VS = vector<string>;

#define ALL(a)  begin((a)),end((a))
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define EB emplace_back
#define MP make_pair
#define MT make_tuple
#define SZ(a) int((a).size())
#define SORT(c) sort(ALL((c)))
#define RSORT(c) sort(RALL((c)))
#define UNIQ(c) (c).erase(unique(ALL((c))), end((c)))

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

#define FF first
#define SS second

template<class S, class T>
istream& operator>>(istream& is, pair<S,T>& p){
  return is >> p.FF >> p.SS;
}
template<class T>
istream& operator>>(istream& is, vector<T>& xs){
  for(auto& x: xs)
	is >> x;
  return is;
}
template<class S, class T>
ostream& operator<<(ostream& os, const pair<S,T>& p){
  return os << p.FF << " " << p.SS;
}
template<class T>
ostream& operator<<(ostream& os, const vector<T>& xs){
  for(unsigned int i=0;i<xs.size();++i)
	os << (i?" ":"") << xs[i];
  return os;
}
template<class T>
void maxi(T& x, T y){
  if(x < y) x = y;
}
template<class T>
void mini(T& x, T y){
  if(x > y) x = y;
}
void debug(istringstream&){}
template <char sep=',', class Head, class... Tail>
void debug(istringstream& iss, Head&& head, Tail&&... tail)
{
  string name;
  getline(iss, name, ',');
  cout << sep << name << "=" << head;
  debug(iss, forward<Tail>(tail)...);
}

#ifdef PYONPOI
#define DEBUG(...) \
  do{ \
    istringstream ss(#__VA_ARGS__); \
    debug<' '>(ss, __VA_ARGS__); \
    cout<<endl; \
  }while(0)
#else
#define DEBUG
#endif
void init_io(int argc, char* argv[]){
  cin.tie(0);
  ios_base::sync_with_stdio(false);
#ifdef PYONPOI
  if(argc > 1) {
    ifstream *ifs = new ifstream();
    ifs->open(argv[1]);
    cin.rdbuf(ifs->rdbuf());
  }
#endif
}


const double EPS = 1e-10;
const double PI  = acos(-1.0);
const LL MOD = 1e9+7;

int main(int argc, char* argv[]){
  init_io(argc, argv);

  int N;
  cin >> N;
  VI xs_(N), ys_(N);
  cin >> xs_ >> ys_;

  auto swapv = [](VI& a, VI& b, int i){
    swap(a[i], b[i+1]);
    swap(a[i+1], b[i]);
  };

  const int INF = 1e9;
  int ans = INF;
  int n2 = N / 2 + N % 2;
  REP(b,1<<N){
    if(__builtin_popcount(b) != n2) continue;
    VI as = xs_, bs = ys_;
    vector<PII> keys, rest;
    REP(i,N) {
      if(b>>i&1){
        keys.EB(i % 2 == 0 ? as[i] : bs[i], i);
      }
      else
        rest.EB(i % 2 == 0 ? bs[i] : as[i], i);
    }
    SORT(keys);
    SORT(rest);
    VI tos(N, -1);
    REP(i,N){
      if(i % 2 == 0)
        tos[keys[i/2].SS] = i;
      else
        tos[rest[i/2].SS] = i;
    }

    int op = 0;
    for(int i=0;i<N;++i){
      if(tos[i] == i) continue;
      else{
        FOR(j,i+1,N){
          if(tos[j] == i){
            while(i < j){
              swapv(as, bs, j-1);
              swap(tos[j-1], tos[j]);
              --j;
              ++op;
            }
            break;
          }
        }
      }
    }

    // DEBUG(op);
    // DEBUG(as);
    // DEBUG(bs);

    bool ok = true;
    REP(i,N-1) ok &= as[i] <= as[i+1];

    // DEBUG(ok);

    if(ok) mini(ans, op);
  }

  cout << (ans == INF ? -1 : ans) << endl;

  return 0;
}


Measured memory_bytes: 256