A11105. Curriculum Vitae

Hideo Kojima has just quit his job at Konami. Now he is going to find a new place to work. Despite being such a well-known person, he still needs a CV to apply for a job.

During all his career Hideo has produced $n$ games. Some of them were successful, some were not. Hideo wants to remove several of them (possibly zero) from his CV to make a better impression on employers. As a result there should be no unsuccessful game which comes right after successful one in his CV.

More formally, you are given an array $s_{1},s_{2},...,s_{n}$ of zeros and ones. Zero corresponds to an unsuccessful game, one — to a successful one. Games are given in order they were produced, and Hideo can't swap these values. He should remove some elements from this array in such a way that no zero comes right after one.

Besides that, Hideo still wants to mention as much games in his CV as possible. Help this genius of a man determine the maximum number of games he can leave in his CV.

The first line contains one integer number $n$ ( $1<=n<=100$ ).

The second line contains $n$ space-separated integer numbers $s_{1},s_{2},...,s_{n}$ ( $0<=s_{i}<=1$ ). $0$ corresponds to an unsuccessful game, $1$ — to a successful one.

Print one integer — the maximum number of games Hideo can leave in his CV so that no unsuccessful game comes after a successful one.