#include<bits/stdc++.h>
#define pb push_back
#define fi first
#define se second
#define mp make_pair
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef long double ld;
template <typename T> bool chkmin(T &x,T y){return x>y?x=y,1:0;}
template <typename T> bool chkmax(T &x,T y){return x<y?x=y,1:0;}
ll readint(){
ll x=0,f=1; char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x*f;
}
int n;
int a[100005],nxt[100005];
ll pref[100005];
ll get(int l,int r){
if(l<=r) return pref[r]-pref[l-1];
else return pref[n]-(pref[l-1]-pref[r]);
}
bool check(ll x){
if(pref[n]<x) return false;
int ptr=1;
for(int i=1;i<=n;i++){
while(get(i,ptr)<x) ptr=(ptr%n)+1;
nxt[i]=ptr;
if(ptr==i) ptr=(ptr%n)+1;
}
for(int i=1;i<=n;i++){
ll a=get(i,nxt[i]);
ll b=get((nxt[i]%n)+1,nxt[(nxt[i]%n)+1]);
ll c=get(nxt[(nxt[i]%n)+1]%n+1,nxt[nxt[(nxt[i]%n)+1]%n+1]);
if(a+b+c<=pref[n]) return true;
}
return false;
}
int main(){
n=readint();
for(int i=1;i<=n;i++) a[i]=readint();
for(int i=1;i<=n;i++) pref[i]=pref[i-1]+a[i];
ll l=0,r=1e17,ans=0;
while(l<=r){
ll mid=(l+r)/2;
if(check(mid)) ans=mid,l=mid+1;
else r=mid-1;
}
printf("%lld\n",ans);
return 0;
}
