public class GGT extends MiniJava {
    public static void main (String[] args) {
        int x, y;
        x = read();
        y = read();
        while (x != y) {
            if (x < y) 
                y = y - x;
            else
                x = x - y;
        }
        write(x);
    } // Ende der Definition von main()
} // Ende der Definition der Klasse GGT