#include <iostream>
using namespace std;
class B {
int x;
public:
B(int i = 7) { x = i; }
int get_x() { return x; }
operator int() { return x; }
};
class D : public B {
public:
D(int i = -12)
: B(i)
{
}
D operator+(D a) { return get_x() + a.get_x() + 1; }
};
int main()
{
D a;
int b = 18;
b += a;
cout << b;
return 0;
}