SGU 403 Scientific Problem

403. Scientific Problem

Time limit per test: 0.25 second(s)
Memory limit: 65536 kilobytes

input: standard
output: standard

Once upon a time Professor Idioticideasinventor was travelling by train. Watching cheerless landscape outside the window, he decided to invent the theme of his new scientific work. All of a sudden a brilliant idea struck him: to develop an effective algorithm finding an integer number, which is x times less than the sum of all its integer positive predecessors, where number x is given. As far as he has no computer in the train, you have to solve this difficult problem.

Input

The first line of the input file contains an integer number x (1 ≤ x ≤ 10⁹).

Output

Output an integer number — the answer to the problem.

Example(s)

sample input	sample output
1	3

 

sample input	sample output
2	5

 1 #include<iostream>  

 2 #include<string.h>  

 3 #include<stdio.h>  

 4 #include<ctype.h>  

 5 #include<algorithm>  

 6 #include<stack>  

 7 #include<queue>  

 8 #include<set>  

 9 #include<math.h>  

10 #include<vector>  

11 #include<map>  

12 #include<deque>  

13 #include<list>  

14 using namespace std;

15 int main()

16 {

17     int x;

18     scanf("%d",&x);

19     printf("%d\n",2*x+1);

20     return 0;

21 } 

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