package no077;

import java.util.Scanner;

public class Main {
	public static final int MAX = 300;
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[MAX];
		for(int i=0;i<n;i++) {
			a[i] = sc.nextInt();
		}
		int ans = 10000000;
		for(int i=1;i<=201;i+=2) {
			int[] b = new int[MAX];
			for(int k=0;k<i;k++) {
				b[k] = (i+1)/2 - Math.abs(i/2-k);
			}
			int x = 0;
			int y = 0;
			for(int k=0;k<MAX;k++) {
				if (a[k] >= b[k]) {
					x += a[k] - b[k];
				}else{
					y += b[k] - a[k];
				}
			}
			if (x < y) {
				continue;
			}
			ans = Math.min(ans, x);
		}
		System.out.println(ans);
	}

}