#include <iostream>
using namespace std;

int main()
{
    int a, b, size = 15;
    
    for (a = size / 2; a <= size; a = a + 2)
        {
            for (b = 1; b < size - a; b = b + 2)
                   cout << " ";
            for (b = 1; b <= a; b++)
                cout << "a";
            for (b = 1; b <= size - a; b++)
                cout << " ";
            for (b = 1; b <= a - 1; b++)
                cout << "A";
            cout << endl;
        }
    for (a = size; a >= 0; a--)
    {
        for (b = a; b < size; b++)
            cout << " ";
        for (b = 1; b <= ((a * 2) - 1); b++)
            cout << "B";
        
        cout << endl;
    }
}