program main
	implicit none
    integer(8) X, A, B
	read(*, *) X, A, B
	A = B - A
	if(A <= 0) then
		write(*, *) 'delicious'
	else if(A <= X) then
		write(*, *) 'safe'
	else
		write(*, *) 'dangerous'
	end if
end program main