3. (8 points) The advertising slogan for battery $A$ is “One is stronger than six”, which means that battery $A$ is more efficient than other batteries. We assume that the power of one $A$ battery is 6 times that of a $B$ battery. There are two clocks with the same power consumption rate. Now, 4 $A$ batteries are installed in clock A, and 3 $B$ batteries are installed in clock B. As a result, clock B operates normally for 2 months before the batteries are depleted. How many more months can clock A operate normally compared to clock B? $\qquad$ months.