Help me in solving CPPFALL431 problem

help
,
1

My issue

oupput is not coming i am trieng hard to complte this problem

My code

#include <iostream>
using namespace std;

class A {
protected:
    int a;
public:
    A(int x) : a(x) {}
    virtual void display() {
        cout << "a: " << a << endl;
    }
};

class B : virtual public A {
protected:
    int b;
public:
    B(int x, int y) : A(x), b(y) {}
    void display() override {
        cout << "a: " << a << "\nb: " << b << endl;
    }
};

class C : virtual public A {
protected:
    int c;
public:
    C(int x, int z) : A(x), c(z) {}
    void display() override {
        cout << "a: " << a << "\nc: " << c << endl;
    }
};

class D : public B, public C {
public:
    D(int x, int y, int z) : A(x), B(x, y), C(x, z) {}
    void display() override {
        cout << "a: " << a << "\nb: " << b << "\nc: " << c << endl;
    }
};

int main() {
    int a, b, c;
    cin >> a >> b >> c;
    D obj(a, b, c);
    obj.display();
    return 0;
}

Learning course: Learn Programming and Problem Solving using C++
Problem Link: https://www.codechef.com/learn/course/sit-cpp-fall/SITFALL60/problems/CPPFALL431