#include <iostream>
#include <vector>
#include <random>
#include <string>
using namespace std;

class A
{
public:
    static int NumberOfClasses;
    A()
    {
        NumberOfClasses++;
    }

};
class B : public A
{
public:
B()
{
    NumberOfClasses++;
}
static int NumberOfClasses;
    static float getStatistic()
    {
        return (float)NumberOfClasses / (float)A::NumberOfClasses;
    }
};
class C : public A
{
public:
    C()
    {
        NumberOfClasses++;
    }
   static int NumberOfClasses;
    static float getStatistic()
    {
        return (float)NumberOfClasses / (float)A::NumberOfClasses;
    }
};
class D : public A
{
public:
    D()
    {
        NumberOfClasses++;
    }
    static int NumberOfClasses;
    static float getStatistic()
    {
        return (float)NumberOfClasses / (float)A::NumberOfClasses;
    }
};
int A::NumberOfClasses = 0;
int B::NumberOfClasses = 0;
int C::NumberOfClasses = 0;
int D::NumberOfClasses = 0;
int main()
{
    B b1;
    B b2;
    B b3;
    C c1;
    C c2;
    D d1;
    cout << B::getStatistic() << endl << C::getStatistic() << endl << D::getStatistic();

	system ("pause");
    return 0;
}