#include <bits/stdc++.h>
using namespace std;
int main( )
{
	int a[1000];
	int n,include;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
		a[0]=a[i];
		if(a[0]<=a[i]&&a[i]-18>=a[0]) 
		{
			a[0]+=a[i]-a[0]; 
			include=(a[i]-a[0])*(a[i]-a[0]);
		}
			else if(a[0]>=a[i]&&a[0]-18>=a[0]) 
			{
				a[i]+=a[i]-a[0]; 
				include=(a[0]-a[i])*(a[0]-a[i]);
			}
	}	
	cout<<include;
	return 0;
}