#include <bits/stdc++.h>
#define int long long
using namespace std;
#define lowbit(x) (x & (-x))

const int maxn = 2e5+8, inf = 1e18+9, mod = 1e9+7;

int n, m, a[maxn], b[maxn], bit[maxn], pos[maxn];
map<int, set<int>> mp;

void update(int x, int v) {
    while (x < maxn) bit[x] += v, x += lowbit(x);
}

int ask(int x) {
    int ans = 0;
    while (x) ans += bit[x], x -= lowbit(x);
    return ans;
}

void solve() {
    int i, j, ans = 0;
    cin >> n;
    for (i = 1; i <= n; i++) cin >> a[i], a[i] += i;
    for (i = 1; i <= n; i++) cin >> b[i], b[i] += i;
    for (i = 1; i <= n; i++) mp[a[i]].insert(i);
    for (i = 1; i <= n; i++) {
        if (mp[b[i]].empty()) return (void)(cout << -1 << endl);
        auto it = mp[b[i]].begin();
        pos[i] = *it;
        mp[b[i]].erase(it);
    }
    for (i = 1; i <= n; i++) {
        ans += ask(n) - ask(pos[i]);
        update(pos[i], 1);
    }
    cout << ans << endl;
}

signed main() {
    ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0); //cout << fixed << setprecision(15);
    int t = 1; //cin >> t;
    while (t--) solve();
    return 0;
}


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

#define e1 first
#define e2 second
#define pb push_back
#define mp make_pair
#define boost {ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); }
#define eb emplace_back
#define OUT(x) {cout << x; exit(0); }
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define scanf(...) scanf(__VA_ARGS__)?:0
typedef long long int ll;
typedef unsigned long long ull;
typedef pair <int, int> PII;
typedef pair <ll, ll> PLL;
typedef pair <PLL, int> PLLI;
typedef pair <PII, PII> PP;
typedef pair <PII, int> PPI;
typedef pair <int, PII> PIP;
typedef pair <ll, int> PLI;
typedef unsigned int ui;
const int inf = 1e9+9;
const ll MOD = 1e9+696969;
#ifdef DEBUG
template<class T> int size(T &&x) {
	return int(x.size());
}
template<class A, class B> ostream& operator<<(ostream &out, const pair<A, B> &p) {
	return out << '(' << p.first << ", " << p.second << ')';
}
template<class T> auto operator<<(ostream &out, T &&x) -> decltype(x.begin(), out) {
	out << '{';
	for(auto it = x.begin(); it != x.end(); ++it)
		out << *it << (it == prev(x.end()) ? "" : ", ");
	return out << '}';
}
void dump() {}
template<class T, class... Args> void dump(T &&x, Args... args) {
	cerr << x << ";  ";
	dump(args...);
}
#endif
#ifdef DEBUG
  struct Nl{~Nl(){cerr << '\n';}};
# define debug(x...) cerr << (strcmp(#x, "") ? #x ":  " : ""), dump(x), Nl(), cerr << ""
#else
# define debug(...) 0 && cerr
#endif
mt19937_64 rng(0);
int random(int l, int r) {
	return uniform_int_distribution<int>(l, r)(rng);
}

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long LL;
typedef pair<int, int> pii;
typedef vector<int> vi;
const LL INF = 1e18;
const int maxn = 300100;
const int mod = 998244353;
int dr[maxn];

void add(int p, int v) {
	for (; p < maxn; p += p & (-p)) dr[p] += v;
}

int get(int p) {
	int res = 0;
	for (; p > 0; p -= p & (-p)) res += dr[p];
	return res;
}

ll inv(vector <int> &perm) {
	int n = perm.size();
	ll res = 0;
	for (int i=n-1; i>=0; --i) {
		res += get(perm[i]);
		add(perm[i], 1);
	}
	
	return res;
}

void solve() {
	int n;
	cin >> n;
	set <PII> q;
	FOR(i, 0, n-1) {
		int a;
		cin >> a;
		q.insert({a + i, i + 1});
	}
	
	vector <int> perm;
	vector <int> B(n + 1);
	FOR(i, 1, n) {
		cin >> B[i];
	}
	
	FOR(i, 1, n) {
		int a = B[i];
		int co = a + i - 1;
		set <PII> :: iterator szukane = q.lower_bound(make_pair(co, -1));
		if (szukane == q.end() || szukane->first != co) {
			cout << "-1\n";
			return;
		}
		
		perm.push_back(szukane -> e2);
		q.erase(szukane);
	}
	debug(perm);
	cout << inv(perm) << "\n";
}

int main() {
	boost;
	int tests;
	tests = 1;
	//cin >> tests;
	while (tests--) {
		solve();
	}
}

