// template version 1.15
using namespace std;
#include <bits/stdc++.h>

// varibable settings
#define int long long
const int INF=1e18;

// define basic macro {{{
#define _overload3(_1,_2,_3,name,...) name
#define _rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define rep(...) _overload3(__VA_ARGS__,repi,_rep,)(__VA_ARGS__)
#define _rrep(i,n) rrepi(i,0,n)
#define rrepi(i,a,b) for(int i=(int)((b)-1);i>=(int)(a);--i)
#define rrep(...) _overload3(__VA_ARGS__,rrepi,_rrep,)(__VA_ARGS__)
#define each(i,a) for (auto&& i : a)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define pb(a) push_back(a)
#define mp(a, b) make_pair(a, b)
#define mt(a, b, c) make_tuple(a, b, c)
#define divceil(a,b) ((a)+(b)-1)/(b)
#define is_in(x, a, b) ((a)<=(x) && (x)<(b))
#define uni(x) sort(all(x));x.erase(unique(all(x)),x.end())
#define ub upper_bound
#define lb lower_bound
#define posl(A, x) (lower_bound(all(A), x)-A.begin())
#define posu(A, x) (upper_bound(all(A),x)-A.begin())
template<class T> inline void chmax(T &a, const T &b) { if((a) < (b)) (a) = (b); }
template<class T> inline void chmin(T &a, const T &b) { if((a) > (b)) (a) = (b); }

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef long double ld;
typedef pair<int,int> pii;
typedef tuple<int,int,int> iii;

template<typename T> using PQ = priority_queue<T, vector<T>, greater<T>>;
struct Fast { Fast(){ std::cin.tie(0); ios::sync_with_stdio(false); } } fast;

#if defined(PCM) || defined(LOCAL)
  #include "lib/dump.hpp"
#else
  #define dump(...) 42
  #define dump_1d(...) 42
  #define dump_2d(...) 42
  #define cerrendl 42
#endif
//}}}

#define N 61/*{{{*/
string to_bin(int n, int d){
  // nをd桁の2進数で表示する。
  stringstream ss;
  ss << bitset<N>(n);
  return ss.str().substr(N-d, d);
}
// int d = (32 - __builtin_clz(n));  // 桁数
// int f = N - d; to_bin()で返ってきた文字列で最初に1が立っているindex}}}

template<typename T=int> struct bit {//{{{
  int n;
  vector<T> dat;
  vector<T> raw;

  bit(int _n=0){ //{{{
    n = _n;
    dat = vector<T>(n);
    raw = vector<T>(n);
  } //}}}

  bit(vector<T> a){ // {{{
    n = (int)a.size();
    dat = vector<T>(n);
    raw = vector<T>(n);
    for(int i = 0; i<n; i++){
      add(i, a[i]);
      raw[i] = a[i];
    }
  } //}}}

  T sum(int i){ //{{{
    T s = 0;
    while(i >= 0){
      s += dat[i];
      i = (i & (i+1)) - 1;
    }
    return s;
  } //}}}

  T sum(int i, int j){ //{{{  [i, j]
    if(i > j) return 0;
    return sum(j) - sum(i-1);
  } //}}}

  void add(int i, T x){ //{{{
    raw[i] += x;
    while(i < n){
      dat[i] += x;
      i |= i+1;
    }
  } //}}}

  int lower_bound(T x){ // a[0]+...+a[ret] >= x{{{
    int ret = -1;
    int k = 1;
    while(2*k <= n) k <<= 1;
    for( ;k>0; k>>=1){
      if(ret+k < n && dat[ret+k] < x){
        x -= dat[ret+k];
        ret += k;
      }
    }
    return ret + 1;
  } //}}}

  friend ostream& operator<<(ostream &os, bit<T>& b){ //{{{
    os << endl << "  raw:" << b.raw << endl;
    vector<T> acum;
    rep(i, b.n){
      acum.pb(b.sum(i));
    }
    os << "  acm:" << acum << endl;
    return os;
  } //}}}
}; //}}}

signed main() {
  int n;cin>>n;
  vector<int> a(n);
  int V = -1;
  rep(i, n) {
    cin>>a[i];
    chmax(V, a[i]);
  }
  dump(a);
  vector<int> b(n);
  rep(i, n) {
    cin>>b[i];
    chmax(V, b[i]);
  }
  dump(b);

  int ans = INF;
  rep(mask, 1<<n){
    cerrendl;
    string s = to_bin(mask, n);
    reverse(all(s));
    dump(s);
    vvi e(V+1);
    vvi o(V+1);
    vi col(n);
    rep(i, n){
      if (mask&(1<<i)){
        col[i] = 1;
        // a[i]
        if ((i%2)==0) e[a[i]].pb(i);
        if ((i%2)==1) o[a[i]].pb(i);
      }
      else{
        // b[i]
        if ((i%2)==0) o[b[i]].pb(i);
        if ((i%2)==1) e[b[i]].pb(i);
      }
    }
    dump(e);
    dump(o);

    vi p(n, -1);
    vi val(n, -1);
    bool check = true;

    int idx = 0;
    rep(v, 1, V+1){
      sort(all(e[v]));
      each(x, e[v]){
        dump(v, x, idx);
        if (idx>=n){
          check = false;
          break;
        }
        p[idx] = x;
        if (col[x]) val[idx] = a[x];
        if (!col[x]) val[idx] = b[x];

        idx += 2;
        dump(idx);
      }
    }

    idx = 1;
    rep(v, 1, V+1){
      sort(all(o[v]));
      each(x, o[v]){
        dump(v, x, idx);
        if (idx>=n){
          check = false;
          break;
        }
        p[idx] = x;
        if (col[x]) val[idx] = a[x];
        if (!col[x]) val[idx] = b[x];

        idx += 2;
      }
    }
    dump(p);
    dump(val);
    dump(check);
    // 単調増加かチェック


    rep(i,1,n){
      if (val[i-1]>val[i]){
        check = false;
      }
    }
    dump(check);
    if (!check) continue;

    bit<int> bt(51);
    bt.add(p[0], 1);
    int cnt = 0;
    rep(i, 1, n){
      dump(p[i]);
      cnt += bt.sum(p[i], 50);
      bt.add(p[i], 1);
    }
    dump(cnt);
    chmin(ans, cnt);

  }
  cout << (ans==INF ? -1 : ans) << endl;
  return 0;
}


Measured memory_bytes: 384