365. Ships of the Desert

Time limit per test: 0.25 second(s)
Memory limit: 65536 kilobytes
input: standard
output: standard

During one of his trips Vasya went to Egypt. He needed to cross the desert. This is pretty easy to do because of caravans furrowing the desert. The only thing Vasya needed was to buy a ticket. Inhabitants told Vasya that he should buy peculiar ticket to get a lot of luck in his life. Vasya found out that peculiar ticket is so-called ticket-dromedary (named after the dromedary camels that are crossing the desert). Ticket can be called dromedary if digits in its number are going in non-descending order and then in non-ascending order (length of any digit group may equals to zero). Vasya has interesting question: how many tickets-dromedaries exist with number consisting of exactly S digits?

The first line of the input file contains S (1 ≤ S ≤ 20) — amount of digits in the ticket number. Ticket number may have leading zeroes.

Print amount of tickets-dromedaries with exactly S digits.

sample input
sample output

sample input
sample output

Online Contester Team © 2002 - 2010. All rights reserved.