#include <iostream>
using namespace std;
const int N = 1010;
int a[N];
int main(){
    int n;  cin >> n;
    for(int i = 0; i < n; i ++ )    cin >> a[i];
    int res = 1e8;
    for(int i = 0; i + 17 <= 100; i ++ ){
        int tmp = 0, l = i, r=  i + 17;
        for(int j = 0; j < n; j ++ ){
            if(a[j] < l)    tmp += (l - a[j]) * (l - a[j]);
            else if(a[j] > r)   tmp += (r - a[j]) * (r - a[j]);
        }
        res = min(res, tmp);
    }
    cout << res << endl;
    return 0;
}