Необработанное исключение: "Нарушение прав доступа при записи"

#include <iostream>
#include <string>
using namespace std;
struct Student
{
    string Family_name;
    int Number_group;
    float ball[5];
};
const int MAX=3;
int main()
{
    float midarifmetik[MAX];
Student group[MAX];
for (int i=0;i<MAX;++i)
{
    cout << "Enter you family name" << endl;
    cin >> group[i].Family_name;
    cout << "Enter you number group" << endl;
    cin >> group[i].Number_group;
    cout << "Enter you ball" << endl;
    cin >> group[i].ball[1];
      cin >> group[i].ball[2];
        cin >> group[i].ball[3];
          cin >> group[i].ball[4];
            cin >> group[i].ball[5];
    midarifmetik[i] = (group[i].ball[1] + group[i].ball[2]+group[i].ball[3]
    + group[i].ball[4]+group[i].ball[5])/5;
    cout << "======================" << endl;
}
 
    for (int x=0;x<MAX;++x)
    {
        if(midarifmetik[x] >= 4)
        {
            cout << " Name: " << group[x].Family_name << " / Group: " ;
              cout << group[x].Number_group << " / Midball = ";
                cout << midarifmetik[x] << endl;
 
        }
        else
            cout << "DELETED (Mid ball < 4.0)" << endl;
    }
    system("pause");
    return 0;
}