You are responsible for the logistics of a wine production factory. There are n containers and every day one container is filled with wine. For each container, you know the number of days it should be kept closed before opening. You’d like to minimize the time it will take to open all the containers.
Input
The first line of the input contains a single integer n (1 ≤ n ≤ ).
The next line contains n space-separated integers (1 ≤ ≤ ) the number of days each of the containers need to be kept closed before opening.
Output
The program should print the least amount of time you need to wait until all the containers can be opened.
Examples
Input
Output
4
2 3 4 3
6
6
39 19 38 39 22 35
41
Explanation
Example 1 (enumerated numbers represent the day numbers):
Fill the container that needs to be kept closed for 4 days
Fill the container that needs to be kept closed for 3 days
Fill the container that needs to be kept closed for 3 days
Fill the container that needs to be kept closed for 2 days
Open the containers filled during Day 1 and Day 2
Open the containers filled during Day 3 and Day 4 ⇒ all are open