#include <iostream>
#include <algorithm>
#include <functional>
#include <string>
#include <climits>
#include <vector>
#include <numeric>
#include <complex>
using namespace std;

#define long __int64
//#define __int64 long long
#define REP(i,a,b) for(int i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
const int Vecy[4] = {0,-1,0,1};
const int Vecx[4] = {1,0,-1,0};

int main(){
	int n;
	int from[100] = {0};
	int to[100];//1,4,9,16...
	int sum = 0;
	int weight;
	int check;
	int plus = 0;
	int minus = 0;
	
	cin >> n;
	rep(i,n){
		cin >> from[i];
		sum += from[i];
	}
	
	check = 4;
	weight = 1;
	while(sum >= check){
		weight += 2;
		check += weight + 2;
	}
	
	for(int i=0; i<=weight/2; i++){
		to[i] = i + 1;
		to[weight-i-1] = i + 1;
	}
	
	for(int i=0; i<weight; i++){
		//cout << to[i] << " - " << from[i] << " = " << to[i] - from[i] << endl;
		if(from[i] < to[i]){
			plus += to[i] - from[i];
		}else if(from[i] > to[i]){
			minus += from[i] - to[i];
		}
	}
	
	cout << max(plus, minus) << endl;
	
    return 0;
}