Iahub got bored, so he invented a game to be played on paper. He writes n integers a 1, a 2, ..., a n . Each of those integers can be either 0 or 1. He's allowed to do exactly one move: he chooses two indices i and j (1 ≤ i ≤ j ≤ n ) and flips all values a k for which their positions are in range [i, j] (that is i ≤ k ≤ j ). Flip the value of x means to apply operation x = 1 - x . The goal of the game is that after exactly one move to obtain the maximum number of ones. Write a program to solve the little game of Iahub.

输入描述:

The first line of the input contains an integer n (1 ≤ n ≤ 100). In the second line of the input there are n integers: a1, a2, ..., an. It is guaranteed that each of those n values is either 0 or 1.

输出描述:

Print an integer — the maximal number of 1s that can be obtained after exactly one move.

备注:

In the first case, flip the segment from 2 to 5 (i = 2, j = 5). That flip changes the sequence, it becomes: [1 1 1 0 1]. So, it contains four ones. There is no way to make the whole sequence equal to [1 1 1 1 1].In the second case, flipping only the second and the third element (i = 2, j = 3) will turn all numbers into 1.