Problem:
Score : 200 points

Problem Statement

Evi has N integers a_1,a_2,..,a_N. His objective is to have N equal integers by transforming some of them.

He may transform each integer at most once. Transforming an integer x into another integer y costs him (x-y)^2 dollars. Even if a_i=a_j (i≠j), he has to pay the cost separately for transforming each of them (See Sample 2).

Find the minimum total cost to achieve his objective.

Constraints

1≦N≦100

-100≦a_i≦100

Input

The input is given from Standard Input in the following format:

N
a_1 a_2 ... a_N

Output

Print the minimum total cost to achieve Evi's objective.

Sample Input 1

2
4 8

Sample Output 1

8

Transforming the both into 6s will cost (4-6)^2+(8-6)^2=8 dollars, which is the minimum.

Sample Input 2

3
1 1 3

Sample Output 2

3

Transforming the all into 2s will cost (1-2)^2+(1-2)^2+(3-2)^2=3 dollars. Note that Evi has to pay (1-2)^2 dollar separately for transforming each of the two 1s.

Sample Input 3

3
4 2 5

Sample Output 3

5

Leaving the 4 as it is and transforming the 2 and the 5 into 4s will achieve the total cost of (2-4)^2+(5-4)^2=5 dollars, which is the minimum.

Sample Input 4

4
-100 -100 -100 -100

Sample Output 4

0

Without transforming anything, Evi's objective is already achieved. Thus, the necessary cost is 0.

Solution in Kotlin (1.0.0) (judge verdict: Accepted)

/**
 * Created by karayuu on 2018/05/22
 */
fun main(args: Array<String>) {
    val n = readLine()!!.toInt()
    val list = readLine()!!.split(" ").map { it.toInt() }

    /* #roundToInt()で四捨五入->平均を出す。平均にそろえるのが最もコストが少ない...と思う */
    val average = Math.round(list.average()).toInt()

    val cost = list.sumBy { (it - average).squared() }

    print(cost)
}

fun Int.squared() : Int = this * this

/* kotlin 1.0.0 は#roundToInt()がないので作るしかない... -> Mathクラスを使うのが楽。*/
/*
fun Double.roundToInt() : Int {
    return if (this < 1.5) {
        this.toInt()
    } else {
        this.toInt() + 1
    }
}
*/