Let’s define a function over the non-negative integers in the following manner:

- P(n) = n when
*n*is a one-digit integer. - P(n) = the product of all the digits of
*n*when*n*> 9.

Example: P(1729) = 126, because 1 × 7 × 2 × 9 = 126.

Evaluate the following:

Note: this problem was shared to WTM by Reza Kassai, of Shiraz, Iran.