int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    int tests;
    int colleges;
    cin >> tests;
    vector<vector <int> > data(tests);
    for (int i = 0 ; i < tests;i++){
        cin >> colleges;
        data[i] = vector<int>(colleges);
        int min;
        for (int n = 0; n < colleges; n++){
            int num;
            cin >> num;


            data[i][n] = num;
            if (data[i][n] < data[i][0])
                swap (data[i][n], data[i][0]);
        }
    }

    for (auto set : data ){
        int result = INT_MAX;
        int floor=set[0];
        for (int i = 0; i <= 4; i++){
            set[0] -=i;
            floor = set[0];
            int count = 0;
            if (i > 0 && i < 3)
              count++;
            if (i > 2)
              count += 2;
            for (auto number : set){
                if (floor == number){
                    continue;
                }
                int dif = number-floor;
                int mod = dif % 5;
                if (mod == 0 )
                    count += dif/5;
                if (mod == 1 || mod == 2)
                {
                    count += (dif-mod)/5 + 1;
                }
                if (mod == 3 || mod == 4)
                {
                    count += (dif-mod)/5 + 2;
                }
            }

            if (result > count)
                result = count;

        }
        cout << result << endl;
    }
    return 0;
}