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

#include<iostream>  
#include<string.h>  
#include<stdio.h>  
#include<ctype.h>  
#include<algorithm>  
#include<stack>  
#include<queue>  
#include<set>  
#include<math.h>  
#include<vector>  
#include<map>  
#include<deque>  
#include<list>  
using namespace std;
int main()
{
    int x;
    scanf("%d",&x);
    printf("%d\n",2*x+1);
    return 0;
}