A Young's double-slit experiment is performed using monochromatic light of wavelength $\lambda $. The intensity of light at a point on the screen, where the path difference is $\lambda $, is K units. The intensity of light at a point where the path difference is ${\lambda \over 6}$ is given by ${{nK} \over {12}}$, where n is an integer. The value of n is __________.