#include<iostream>
#include<algorithm>
using namespace std;
int a[50005], b[2000005] = {};
const int M = 1000000;
int main()
{
	int n;
	cin >> n;
	for (int i = 1; i <= n; i++)
	{
		cin >> a[i];
	}
	int ans = 0;
	ans += a[1];
	b[M+a[1]]=1;
	for (int i = 2; i <= n; i++)
	{
		for (int j = M + a[i],k=0;; k++)
		{
			if (b[j + k]||b[j-k])
			{
				ans += k;
				break;
			}
		}
		b[M + a[i]]=1;
	}
	cout << ans;
	return 0;
}