Probability

Cards are drawn one after the other without replacement from a well shuffled pack of cards until and ace card appears. If the probability that exactly 5 cards are drawn before the first ace card appears is $\frac{4}{49}\left(\frac{p_1 \cdot p_2 \cdot p_3}{p_4 \cdot p_5 \cdot p_6}\right),\left(p_i\right.$ is prime, $\left.i=1,2,3,4,5,6\right)$ then $\left(\max \left\{p_i\right\}-\min \left\{p_i\right\}\right)=$