#include <bits/stdc++.h>
#include <unistd.h>
 
using namespace std;
 
typedef long long ll;
typedef pair<ll,ll> P;
 
long long int INF = 3e18;
const ll fact_table = 800008;
double Pi = 3.1415926535897932384626;
 
vector<P> G[550010];
//vector<P> tree[500010];
priority_queue <ll> pql;
priority_queue <P> pqp;
//big priority queue
priority_queue <ll,vector<ll>,greater<ll> > pqls;
// priority_queue <P,vector<P>,greater<P> > pqps;
//small priority queue
//top pop
 
ll dx[8]={1,0,-1,0,1,1,-1,-1};
ll dy[8]={0,1,0,-1,1,-1,-1,1};
char dir[] = "DRUL";
//↓,→,↑,←
 
 
#define p(x) cout<<x<<"\n";
#define el cout<<endl;
#define pe(x) cout<<(x)<<" ";
#define ps(x) cout<<fixed<<setprecision(25)<<x<<endl;
#define pu(x) cout<<(x);
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define CLEAR(a) a = decltype(a)(); 
 
 
//ll mod = 998244353;
ll mod = 1000000007;
 
ll rui(ll number1,ll number2){
 
    if(number2 == 0){
        return 1;
    }else{
        ll number3 = rui(number1,number2 / 2);
        number3 *= number3;
        number3 %= mod;
        if(number2%2==1){
            number3 *= number1;
            number3 %= mod;
        }
        return number3;
    }
}
ll gcd(ll number1,ll number2){
 
    if(number1 > number2){
        swap(number1,number2);
    }
    if(number1 == 0 || number1 == number2){
        return number2;
    }else{
        return gcd(number2 % number1,number1);
    }
}
void YES(bool condition){
 
    if(condition){
        p("YES");
    }else{
        p("NO");
    }
    return;
}
void Yes(bool condition){
 
    if(condition){
        p("Yes");
    }else{
        p("No");
    }
    return;
}
 
/*
ll fact[fact_table + 5],rfact[fact_table + 5];
 
void c3_init(){
    fact[0] = rfact[0] = 1;
    for(ll i=1; i<=fact_table; i++){
        fact[i] = (fact[i-1]*i) % mod;
    }
    rfact[fact_table] = rui(fact[fact_table],mod - 2);
    for(ll i=fact_table; i>=1; i--){
       rfact[i-1] = rfact[i] * i;
       rfact[i-1] %= mod;
    }
    return;}
ll c3(ll n,ll r){
    return (((fact[n] * rfact[r]) % mod ) * rfact[n-r]) % mod;}
*/
 
ll n,m,num,sum,a,b,c,d,e,h,p,q,r,l;
ll k;
ll ans;
ll x[500005], y[500005];
ll dp[280000][55];
ll memo[280000][55];
bool used[50005];

int main(){
    cin >> n;
    for(ll i=0;i<n;i++){
        cin >> x[i];
        used[x[i]] = true;
    }
    for(ll i=0;i<n;i++){
        cin >> y[i];
        used[y[i]] = true;
    }
    used[0] = true;
    ll bit = (1ll << n);
    for(ll i=0;i<bit;i++){
        for(ll j=0;j<=50;j++){
            dp[i][j] = INF;
        }
    }
    dp[0][0] = 0;
    for(ll i=0;i<bit;i++){
        for(ll j=0;j<n;j++){
            // memo[i][j]を求める
            for(ll k=j+1;k<n;k++){
                if((i >> k) & 1)memo[i][j] ++;
            }
        }
    }
    for(ll i=0;i<bit;i++){
        ll idx = 0;
        for(ll k=0;k<n;k++){
            if((1ll << k) & i)idx++;
        }
        for(ll j=0;j<=50;j++){
            if(!used[j])continue;
            // dp[i][j]から配る先を求めるよ
            for(ll k=0;k<n;k++){
                // すでに使っているなら
                if((i >> k) & 1)continue;
                ll afterbit = i ^ (1ll << k);
                bool flip = (abs(idx - k) % 2 == 0);
                ll value = (flip ? x[k] : y[k]);
                if(value < j)continue;

                ll inversion = memo[i][k];
                dp[afterbit][value] = min(dp[afterbit][value], dp[i][j] + inversion);
            }
        }
    }
    ans = INF;
    for(ll i=0;i<=50;i++){
        ans = min(ans, dp[(1ll << n) - 1][i]);
    }
    if(ans == INF){
        ans = -1;
    }
    p(ans);


    return 0;
}
 











Measured memory_bytes: 247296