program test
implicit none
character::a*4
read*,a
	if('a(1:1)'=='a(2:2)' .or. 'a(2:2)'=='a(3:3)' .or. 'a(3:3)'=='a(4:4)') then
     print*,'Bad'
    else
     print*,'Good'
    end if 
end program test