public class Gcd_dowhile
{
    public static void main(String args[]) 
    {
        int a=12,b=18,k=0;
        System.out.print("Gcd("+a+","+b+")=");
        do 
        {
            k = a % b;
            a = b;
            b = k; 
        }  while (k!=0);
        System.out.println(a);
    }
}