Time Travel

Visit a list of years in the given order. Moving between equal adjacent years costs 0; going to a later year costs 1; going back to an earlier year costs 2. Find the total time.

输入格式

The first line contains n (1..100); the second line contains n years (1..10000).

输出格式

Output the total time.

样例 1

输入：

4
2000 1990 2005 2050

输出：

4

样例 2

输入：

3
2000 2021 2005

输出：

3

样例 3

输入：

3
2021 2021 2005

输出：

2