BISHOPS  Bishops
Yesterday was Sam's birthday. The most interesting gift was definitely the chessboard. Sam quickly learned the rules of chess and defeated his father, all his friends, his little sister, and now no one wants to play with him any more.
So he decided to play with another birthday gift – a Book of Math Problems for Young Mathematicians. He opened the book somewhere in the middle and read the following problem: "How many knights can be placed on a chessboard without threatening each other?" After a while he realized that this was trivial and moved on to the next problem: "How many bishops can be placed on a chessboard without threatening each other?". Sam is in trouble here. He is not able to solve this problem and needs your help.
Sam's chessboard has size N x N. A bishop can move to any distance in any of the four diagonal directions. A bishop threatens another bishop if it can move to the other bishop's position. Your task is to compute the maximum number of bishops that can be placed on a chessboard in such a way that no two bishops threaten each other.
Input
The input file consists of several lines. The line number i contains a single positive integer N representing the size of the ith chessboard. [1 <= N <= 10^100]
Output
The output file should contain the same number of lines as the input file. The ith line should contain one number – the maximum number of bishops that can be placed on ith chessboard without threatening each other.
Example
Input: 2 3 Output: 2 4
hide comments
Viktor Fonic:
20130722 21:02:07
One line with 69 characters in ruby :) 

Raman Shukla:
20130622 06:33:52
For reading End of input use Try except in Python... 

Devashish Mathur:
20130525 18:25:04
how to find last input using python..?? 

ankita:
20130518 05:34:38
how is end of file detected in python? 

Juraj Dudak:
20130515 14:25:54
@zonker


zonker:
20130509 20:56:59
best code I ever wrote...


Harsh Gupta:
20130313 11:47:51
Such a huge input size


alampata:
20130309 10:07:46
can anyone tell me how to end input in C? 

reggaeguitar:
20130227 19:41:49
I used this in Java and got ac


Ashish:
20130216 11:01:01
Finally AC.... After 4 WA... phewww 
Added by:  Roman Sol 
Date:  20050417 
Time limit:  1s 
Source limit:  10000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All 
Resource:  IPSC 2004 