#include <iostream>
#include <algorithm>
#include <cmath>
using namespace std;
const int inf = 1e9+7;
int main()
{
int n;
scanf("%d",&n);
int a[n];
for(int i=0;i<n;i++)
scanf("%d",&a[i]);
int ans = inf;
for(int i=0;i<=100-17;i++)
{
int mon = 0;
for(int j=0;j<n;j++)
{
if(a[j] < i)
mon += (a[j]-i)*(a[j]-i);
else if(a[j] > i+17)
mon += (a[j]-i-17)*(a[j]-i-17);
}
ans = min(ans,mon);
}
printf("%d",ans);
return 0;
}