/* _user_Capricoder_ */
// to Newbiecpp
#include <bits/stdc++.h>
#define int int64_t
#define str string
#define vi vector<int>
#define vc vector<char>
#define vb vector<bool>
#define ii int, int
#define fi first
#define se second
#define all(arr) arr.begin(), arr.end()
#define fd(var, start, end) for(int var = start; var <= end; ++var)
#define bk(var, start, end) for(int var = start; var >= end; --var)
#define farr(var, arr) for(auto var: arr)
#define endl '\n'
#define elif else if
using namespace std;
int _I_cw(int i, int n, vi &a) // cw: clockwise
{
 int k = a[i] % n;
 int t = (i + k + 1) % n;
 if (i == t) return a[i] / n;
 return a[t] + a[i] / n;
}
int _I_acw(int i, int n, vi &a) // acw: anti-clockwise
{
 int k = a[i] % n;
 int t = (i - k - 1 + n) % n;
 if (i == t) return a[i] / n;
 return a[t] + a[i] / n;
}
void _input(int&, vi&);
void _solve(int, vi&);
signed main()
{

 ios::sync_with_stdio(0);
 cin.tie(0); cout.tie(0);
 int n;
 vi a;
 _input(n, a);
 _solve(n, a);
 return 0;

}
void _input(int &n, vi &a)
{
 cin >> n;
 a.assign(n, 0);
 farr(&i, a) cin >> i;
}
void _solve(int n, vi &a)
{
 int r = 0;
 fd (i, 0, n - 1)
  r = max({r, _I_acw(i, n, a), _I_cw(i, n, a)});
 cout << r;
}