#include<bits/stdc++.h>
using namespace std;
#define task "a"
#define se second
#define fi first
#define ll long long
#define ii pair<ll, ll>
const long mxN = 1e5 + 7;
int n, a[mxN * 2];
ll pre[mxN * 2];
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
//freopen(task".INP", "r", stdin);
//freopen(task".OUT", "w", stdout);
cin >> n;
for (int i = 1; i <= n; i++)
{
cin >> a[i];
a[i + n] = a[i];
}
for (int i = 1; i <= 2 * n; i++)
pre[i] = pre[i - 1] + a[i];
ll ans = 0;
for (int i = 0; i < n; i++)
{
ll l = 0, r = n;
while (l <= r)
{
int mid = (l + r) / 2;
int j = i + mid;
int k = lower_bound(pre + j + 1, pre + n + i, pre[j] + pre[j] - pre[i]) - pre;
if (pre[i + n] - pre[k] >= pre[j] - pre[i])
{
l = mid + 1;
ans = max(ans, pre[j] - pre[i]);
}
else
r = mid - 1;
}
}
cout << ans;
}
