Pointer Member Variable Initialisation in C++ Classes, with non-Pointer Values

Before I start, I'd just like to point out I've Googled this question for a while now and haven't found a satisfactory answer. I'm also aware of a very similar question on Stack Overflow, but it doesn't help me entirely with my situation.

Here's my code:

class A
{
private:
    int x;
    int y;

public:
A( int x, int y );
// other member functions
};


class B
{
private:
    int score;
    A* a;

public:
    B( int x, int y ); // Regular constructor
    // other member functions
};

Implementation:

// Default constructor with member initialisation
A::A( int x, int y )
    :   x( x ), y( y )
{}

// Default constructor with member initialisation
B::B( int x, int y )
    :   score( 0 ), a( x, y )
{}

The problem I have is with initialising the pointer member variable *a in class B. We are required to pass the x, y coordinates to the class B constructor, but I cannot get g++ to compile this as it is expecting a pointer instead of two integers. I'm having trouble wrapping my head around how to call an initialisation to the *a pointer with x, y as my parameters.

In the assignment question, we aren't asked to initiate the *a pointer member variable to a null pointer, nor are we given a pointer with which to initialise it. We are only given x & y coordinates.

The error I receive when compiling with g++ is:

error: expression list treated as compound expression in mem-initializer [-fpermissive]
  : score( 0 ), a( x, y )

I'd appreciate any feedback, thanks in advance for your help!