public class GCD
{
    public static void main(String[] args) 
    {
        int A, B;

        A = 28;
        B = 36;

        while ( A != 0 && B != 0 )
        {
            if ( A > B )
                A = A - B;
            else
                B = B - A;
        }

        if ( A != 0 )
            System.out.println("GCD = " + A);
        else
            System.out.println("GCD = " + B);
    }
}