#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i=0; i<n; i++)
#define pb push_back

int main() {
    int N; cin >> N;
    int A[N], B[N];
    rep(i, N) cin >> A[i];
    rep(i, N) cin >> B[i];
    
    int dp[1<<N][N];
    rep(i, 1<<N) rep(j, N) dp[i][j] = 10000;
    dp[0][0] = 0;
    
    rep(S, 1<<N) rep(i, N) {
        int cnt = 0;
        rep(j, N) if ((S>>j)&1) cnt++;
        rep(j, N) {
            if ((S>>j)&1) continue;
            if (S!=0) {
                int now;
                if ((cnt-j)%2==0) now = A[j];
                else now = B[j];
                int prev;
                if ((cnt-1-i)%2==0) prev = A[i];
                else prev = B[i];
                if (prev>now) continue;
            }
            int idx = j;
            for (int k=j+1; k<N; k++) if ((S>>k)&1) idx++;
            dp[S|(1<<j)][j] = min(dp[S|(1<<j)][j], dp[S][i]+idx-cnt);
        }
    }
    
    int ans = 10000;
    rep(i, N) ans = min(ans, dp[(1<<N)-1][i]);
    if (ans==10000) cout << -1 << endl;
    else cout << ans << endl;
}