var a,b,c:longint;
    f:text;
begin
     assign(f,'cmmdc.in');
     reset(f);
              read(f,a,b);
     close(f);
     while b<>0 do
     begin
          c:=b;
          b:=a mod b;
          a:=c;
     end;
     assign(f,'cmmdc.out');
     rewrite(f);

     if a=1 then
        write(f,0)
        else
            write(f,a);
     close(f);
end.