#include <bits/stdc++.h>
#include <unistd.h>

using namespace std;

#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl
#define DEBUG_MAT(v) cerr<<#v<<endl;for(int i=0;i<v.size();i++){for(int j=0;j<v[i].size();j++) {cerr<<v[i][j]<<" ";}cerr<<endl;}


typedef long long ll;

#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(int i=0;i<(n);i++)
#define rep1(i,n) for(int i=1;i<=(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
//const ll MOD = 1000000007;
const ll MOD = 998244353;
const double pi = 3.14159265358979323846;
#define Sp(p) cout<<setprecision(15)<< fixed<<p<<endl;
int dx[4] = { -1,0, 1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
// #define mp make_pair
//#define endl '\n'

int main() {
  int n;
  cin >> n;
  vl a(n), b(n);
  rep (i, n) cin >> a[i];
  rep (i, n) cin >> b[i];
  
  rep (i, n) {
    if (b[i] < a[i]) {
      cout << -1 << endl;
      return 0;
    }
  }

  priority_queue<pll> pq;
  rep (i, n) {
    pq.push(pii(b[i], i));
  }

  ll ans = 0;
  while (not pq.empty()) {
    ll x = pq.top().first, i = pq.top().second;
    pq.pop();
    if (x == a[i]) continue;
    //DEBUG_VEC(b);
    //DEBUG(pll(x, i));
    ll x1 = b[(i - 1 + n) % n], x2 = b[(i + 1) % n];
    if (x - x1 - x2 <= 0) {
      cout << -1 << endl;
      return 0;
    }

    if (a[i] >= x1 and a[i] >= x2) {
      ll sa = x - a[i];
      if (sa % (x1 + x2) != 0) {
        cout << -1 << endl;
        return 0;
      }
      else {
        ans += sa / (x1 + x2);
        b[i] = a[i];
        continue;
      }
    }
    else {
      ll xma = max(x1, x2);
      ll sa = x - xma;
      ll num = sa / (x1 + x2) + 1;
      ans += num;
      x -= (x1 + x2) * num;
      b[i] = x;
      if (x < a[i]) {
        cout << -1 << endl;
        return 0;
      }
      else if (x > a[i]) {
        pq.push(pii(x, i));
      }
    }
  }
  cout << ans << endl;
}


// int main() {
//   int h, w;
//   cin >> h >> w;

//   vii a(h, vi(w));
//   //*
//   vi v(h*w);
//   rep (i, h*w) v[i] = i;
//   std::random_device seed_gen;
//   std::mt19937 engine(seed_gen());
//   std::shuffle(v.begin(), v.end(), engine);
//   rep (i, h) {
//     rep (j, w) {
//       a[i][j] = v[i*h + j];
//     }
//   }
//   //*/
//   /*
//   rep (i, h) {
//     rep (j, w) {
//       cin >> a[i][j];
//       a[i][j]--;
//     }
//   }
//   //*/

//   //*
//   rep (i, h) {
//     rep (j, w) {
//       cout << a[i][j] + 1 << " ";
//     }
//     cout << endl;
//   }
//   //*/

//   vii b(h, vi(w, -1));
//   vector<vector<bool>> used(w, vector<bool>(h));
//   rep (i, h) {
//     int idx = 0;
//     while (idx < w) {
//       vii pre_b = b;
//       rep (j, w) {
//         int gyou = a[i][idx] / w;
//         if (b[i][j] != -1) continue;
//         if (not used[j][gyou]) {
//           used[j][gyou] = true;
//           b[i][j] = a[i][idx];
//           idx++;
//           if (idx == w) break;
//         }
//       }
//       if (idx != w and b == pre_b) {
//         DEBUG_MAT(used);
//         DEBUG_MAT(b);
//         return 0;
//       }
//     }
//   }

//   //DEBUG("B");
//   rep (i, h) {
//     rep (j, w) {
//       cout << b[i][j] + 1 << " ";
//     }
//     cout << endl;
//   }

//   vii c(h, vi(w));
//   rep (j, w) {
//     vi temp(h);
//     rep (i, h) temp[i] = b[i][j];
//     sort(all(temp));
//     rep (i, h) {
//       c[i][j] = temp[i];
//     }
//   }

//   //DEBUG("C");
//   rep (i, h) {
//     rep (j, w) {
//       cout << c[i][j] + 1 << " ";
//     }
//     cout << endl;
//   }
// }
// //*/


Measured memory_bytes: 9328