What is the length of the shortest pipe, of internal radius , that can fully contain balls of radii where ?
Give your answer in micrometres ( ) rounded to the nearest integer.
Input Format
The first line of each test file contains two-separated integers and .
The next line contains space-separated integers .
Constraints
- .
- .
- .
- are pairwise distinct.
Output Format
Print your answer in one line.
Sample Input 0
2 1
2
Sample Output 0
4000
Sample Input 1
5 2
3 4
Sample Output 1
13325
Sample Input 2
100 5
61 62 63 64 65
Sample Output 2
530707