#D11755. Three Parts of the Array
Three Parts of the Array
Three Parts of the Array
You are given an array d_1, d_2, ..., 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:
$$$sum_1 = ∑_{1 ≤ i ≤ a}d_i, sum_2 = ∑_{a + 1 ≤ i ≤ a + b}d_i, sum_3 = ∑_{a + b + 1 ≤ i ≤ a + b + c}d_i.$ $$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.
Input
The first line of the input contains one integer n (1 ≤ n ≤ 2 ⋅ 10^5) — the number of elements in the array d.
The second line of the input contains n integers d_1, d_2, ..., d_n (1 ≤ d_i ≤ 10^9) — the elements of the array d.
Output
Print a single integer — the maximum possible value of sum_1, considering that the condition sum_1 = sum_3 must be met.
Obviously, at least one valid way to split the array exists (use a=c=0 and b=n).
Examples
Input
5 1 3 1 1 4
Output
5
Input
5 1 3 2 1 4
Output
4
Input
3 4 1 2
Output
0
Note
In the first example there is only one possible splitting which maximizes sum_1: [1, 3, 1], [~], [1, 4].
In the second example the only way to have sum_1=4 is: [1, 3], [2, 1], [4].
In the third example there is only one way to split the array: [~], [4, 1, 2], [~].
inputFormat
Input
The first line of the input contains one integer n (1 ≤ n ≤ 2 ⋅ 10^5) — the number of elements in the array d.
The second line of the input contains n integers d_1, d_2, ..., d_n (1 ≤ d_i ≤ 10^9) — the elements of the array d.
outputFormat
Output
Print a single integer — the maximum possible value of sum_1, considering that the condition sum_1 = sum_3 must be met.
Obviously, at least one valid way to split the array exists (use a=c=0 and b=n).
Examples
Input
5 1 3 1 1 4
Output
5
Input
5 1 3 2 1 4
Output
4
Input
3 4 1 2
Output
0
Note
In the first example there is only one possible splitting which maximizes sum_1: [1, 3, 1], [~], [1, 4].
In the second example the only way to have sum_1=4 is: [1, 3], [2, 1], [4].
In the third example there is only one way to split the array: [~], [4, 1, 2], [~].
样例
3
4 1 2
0
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