You are given an array $d_1, d_2, \dots, d_n$ consisting of $n$ integer numbers.

Your task is to split this array into three parts (some of which may be empty) in such a way that each element of the array belongs to exactly one of the three parts, and each of the parts forms a consecutive contiguous subsegment (possibly, empty) of the original array. 

Let the sum of elements of the first part be $sum_1$, the sum of elements of the second part be $sum_2$ and the sum of elements of the third part be $sum_3$. Among all possible ways to split the array you have to choose a way such that $sum_1 = sum_3$ and $sum_1$ is maximum possible.

More formally, if the first part of the array contains $a$ elements, the second part of the array contains $b$ elements and the third part contains $c$ elements, then:

$$sum_1 = \sum\limits_{1 \le i \le a}d_i,$$ $$sum_2 = \sum\limits_{a + 1 \le i \le a + b}d_i,$$ $$sum_3 = \sum\limits_{a + b + 1 \le i \le a + b + c}d_i.$$

The sum of an empty array is $0$.

Your task is to find a way to split the array such that $sum_1 = sum_3$ and $sum_1$ is maximum possible.
The first line of the input contains one integer $n$ ($1 \le n \le 2 \cdot 10^5$) — the number of elements in the array $d$.

The second line of the input contains $n$ integers $d_1, d_2, \dots, d_n$ ($1 \le d_i \le 10^9$) — the elements of the array $d$.
5
1 3 1 1 4
5
5
1 3 2 1 4
4
3
4 1 2
0
1
1000000000
0
2
1 1
1
5
1 3 5 4 5
9
#_________________ Mukul Mohan Varshney _______________#
 
#Template
import sys
import os
import math
import copy
from math import gcd
from bisect import bisect
from io import BytesIO, IOBase
from math import sqrt,floor,factorial,gcd,log,ceil
from collections import deque,Counter,defaultdict
from itertools import permutations, combinations
import itertools
 
#define function 
def Int(): return int(sys.stdin.readline())
def Mint(): return map(int,sys.stdin.readline().split())
def Lstr(): return list(sys.stdin.readline().strip())
def Str(): return sys.stdin.readline().strip()
def Mstr(): return map(str,sys.stdin.readline().strip().split())
def List(): return list(map(int,sys.stdin.readline().split()))
def Hash(): return dict()
def Mod(): return 1000000007
def Ncr(n,r,p): return ((fact[n])*((ifact[r]*ifact[n-r])%p))%p
def Most_frequent(list): return max(set(list), key = list.count)
def Mat2x2(n): return [List() for _ in range(n)]
def Lcm(x,y):  return (x*y)//gcd(x,y)
def dtob(n): return bin(n).replace("0b","")
def btod(n): return int(n,2)  
def binary(s,e,x,q):
     while(s<=e):
          mid=(s+e)//2
          if(x[mid]<q):
               s=mid+1
          elif(x[mid]>q):
               e=mid-1
          else:
               return mid
     return s
     
     
   
# Driver Code     
def solution():
     #for _ in range(Int()):
          n=Int()
          l=List()
          ans=0
          i=0
          j=n-1
          ls,rs=0,0
          while(i<=j):
               if(ls==rs):
                    ans=ls
                    ls+=l[i]
                    i+=1
               elif(ls>rs):
                    rs+=l[j]
                    j-=1
               elif(ls<rs):
                    ls+=l[i]
                    i+=1
          if(ls==rs):
               print(ls)
          else:
               print(ans)

#Call the solve function          
if __name__ == "__main__":
     solution()  
