WOOT

/*
ID: victao1
LANG: C++
TASK: skidesign
*/
#include <iostream>
#include <cstdio>

using namespace std;

int main(){
    freopen("skidesign.in", "r", stdin);
    freopen("skidesign.out", "w", stdout);
    int N, mincost = 1000000, smallest = 1000, largest = 0, hills[1000];
    cin >> N;
    for(int i = 0; i < N; i++){
        cin >> hills[i];
        if(hills[i] > largest) largest = hills[i];
        if(hills[i] < smallest) smallest = hills[i];
    }
    for(int i = smallest; i <= largest; i++){
        int sum = 0;
        for(int j = 0; j < N; j++){
            if(hills[j] >= i + 17) sum += (hills[j] - 17 - i) * (hills[j] - 17 - i); else
                if(hills[j] <= i)sum += (i - hills[j]) * (i - hills[j]);
        }
        //cout << sum << "\n";
        if(sum < mincost) mincost = sum;
    }
    cout << mincost << "\n";
}