sgu 403. Scientific Problem

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本文介绍了一个有趣的数学问题：给定一个整数x，如何找到一个整数N，使得N的x倍小于从1到N所有整数的总和。文章提供了一种简单有效的算法解决方案，并附带了C++实现代码。

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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

英语弱题意杀，给一个x找出一个N使N的x倍小于1到N的和。

可以有前N-1项和等于x*N，即2*x-1=n

#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;



void solve(){
    int n;
    scanf("%d",&n);
    printf("%d",2*n+1);
}




int main() {


#ifdef LOCAL_DEFINE
    freopen("input.txt", "rt", stdin);
#endif

    solve();


    return 0;
}