//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("unroll-loops")
  
#include <iostream>
#include <stdlib.h>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <assert.h>
#include <memory.h>
#include <time.h>
#include <bitset>
 
#define uint unsigned int
#define ll long long
#define ull unsigned long long
#define ld long double
#define rep(i, l, r) for (int i = (l); i < (r); i++)
#define repb(i, r, l) for (int i = (r); i > (l); i--)
#define sz(a) (int)a.size()
#define fi first
#define se second
#define mp(a, b) make_pair(a, b)
#define rank qwertyuio
#define next dfghjk
#define prev fhsgfhjf
#define plus fsghsf
#define minus ytryr
  
using namespace std;
  
inline bool setmin(int &x, int y) { return (y < x) ? x = y, 1 : 0; }
inline bool setmax(int &x, int y) { return (y > x) ? x = y, 1 : 0; }
inline bool setmin(ll &x, ll y) { return (y < x) ? x = y, 1 : 0; }
inline bool setmax(ll &x, ll y) { return (y > x) ? x = y, 1 : 0; }
  
const int N = 18;
const int inf = (int)1e9 + 1;
const ll big = (ll)1e18 + 1;
const int P = 239;
const int P1 = 31;
const int P2 = 57;
const int MOD = (int)1e9 + 7;
const int MOD1 = (int)1e9 + 9;
const int MOD2 = 998244353;
const ld eps = 1e-12;
const double pi = atan2(0, -1);
const int ABC = 26;
 
int a[N], b[N];
int dp[2][1 << N][N * 2];
int ddd[1 << N][N];

int solve(int mask, int j) {
    mask &= ((1 << j) - 1);
    return j - __builtin_popcount(mask);
}

void init(int n) {
    rep(mask, 0, (1 << n)) {
        rep(j, 0, n) {
            ddd[mask][j] = solve(mask, j);
        }
    }
}

int main()
{
    //freopen("a.in", "r", stdin);
    //freopen("a.out", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.precision(20);
    cout << fixed;
    //ll TL = 10.95 * CLOCKS_PER_SEC;
    //clock_t time = clock();
    int n;
    cin >> n;
    init(n);
    vector<int> diff;
    rep(i, 0, n) {
        cin >> a[i];
        diff.push_back(a[i]);
    }
    rep(i, 0, n) {
        cin >> b[i];
        diff.push_back(b[i]);
    }
    sort(diff.begin(), diff.end());
    diff.resize(unique(diff.begin(), diff.end()) - diff.begin());
    rep(i, 0, n) {
        a[i] = lower_bound(diff.begin(), diff.end(), a[i]) - diff.begin();
        b[i] = lower_bound(diff.begin(), diff.end(), b[i]) - diff.begin();
    }
    int p = 0;
    rep(mask, 0, (1 << n)) {
        rep(c, 0, n * 2) {
            dp[p][mask][c] = inf;
        }
    }
    dp[p][0][0] = 0;
    rep(i, 0, n) {
        rep(mask, 0, (1 << n)) {
            fill(dp[p ^ 1][mask], dp[p ^ 1][mask] + n * 2, inf);
        }
        rep(mask, 0, (1 << n)) {
            if (__builtin_popcount(mask) != i) {
                continue;
            }
            rep(c, 0, n * 2) {
                rep(j, 0, n) {
                    if ((mask >> j) & 1) {
                        continue;
                    }
                    if ((i & 1) == (j & 1)) {
                        if (a[j] >= c) {
                            setmin(dp[p ^ 1][mask | (1 << j)][a[j]], dp[p][mask][c] + ddd[mask][j]);
                        }
                    } else {
                        if (b[j] >= c) {
                            setmin(dp[p ^ 1][mask | (1 << j)][b[j]], dp[p][mask][c] + ddd[mask][j]);
                        }
                    }
                }
            }
        }
        p ^= 1;
    }
    int ans = inf;
    rep(c, 0, n * 2) {
        setmin(ans, dp[p][(1 << n) - 1][c]);
    }
    cout << (ans < inf ? ans : -1) << "\n";
    return 0;
}

Measured memory_bytes: 92544