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
malibarbar:
20160823 14:03:48
Ac in one in c++ 

piyush_arora1:
20160812 19:08:47
Don't forget that for n = 0 or n = 1, output is n. Also for input use while(cin >> n). 

baadshah_:
20160622 22:47:50
For input USE: while((scanf("%s",&num))!=EOF) 

avisheksanvas:
20160519 12:38:00
C++ people. After reading in a Character array, store it in an Integer array. It'll make your work easier.


lalit_nit:
20160123 16:21:07
For Java Coders..... in.hasNextBigInteger();...... insted of some input cases...... this costed me 3WA :/ 

aman8soni:
20150708 04:52:15
@rpc1: while(scanf("%d",&t)!=EOF) 

Dushyant Singh:
20150628 07:09:16
@king: I have done it in 36. :) 

saumya:
20141026 10:24:14
Had to learn a little Java just for this question .. finally AC after two compilation errors :P 

stranger:
20140106 06:15:54
@Xvamp999


Shashank Gupta:
20131106 09:25:14
One line, 82 characters in Python. :) Kinda fun. 
Added by:  Roman Sol 
Date:  20050417 
Time limit:  1s 
Source limit:  10000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All 
Resource:  IPSC 2004 