B'There are n armchairs, numbered from 1 to n from left to right. Some armchairs are occupied by people (at most one person per armchair), others are not. The number of occupied armchairs is not greater than frac{n}{2} . For some reason, you would like to tell people to move from their armchairs to some other ones. If the i -th armchair is occupied by someone and the j -th armchair is not, you can tell the person sitting in the i -th armchair to move to the j -th armchair. The time it takes a person to move from the i -th armchair to the j -th one is |i - j| minutes. You may perform this operation any number of times, but these operations must be done sequentially, i. xe2 x80 x89e. you cannot tell a person to move until the person you asked to move in the last operation has finished moving to their destination armchair. You want to achieve the following situation: every seat that was initially occupied must be free. What is the minimum time you need to do it? The first line contains one integer n ( 2 <= n <= 5000 ) -- the number of armchairs. The second line contains n integers a_1, a_2, ... , a_n ( 0 <= a_i <= 1 ). a_i = 1 means that the i -th armchair is initially occupied, a_i = 0 means that it is initially free. The number of occupied armchairs is at most frac{n}{2} . Print one integer -- the minimum number of minutes you have to spend to achieve the following situation: every seat that was initially occupied must be free. In the first test, you can perform the following sequence: In the second test, you can perform the following sequence: In the third test, no seat is occupied so your goal is achieved instantly. '...