Scientific Problem(数学，简单)

Scientific Problem

Time Limit:500MS    Memory Limit:65536KB    64bit IO Format:%I64d & %I64u

SubmitStatusPracticeSGU 403

Description

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 numberx 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.

Sample Input

sample input

sample output

1

3

sample input

sample output

2

5

设答案为n，则nx < 1 +2 +3 + ... + n - 1 ,得到 n > 2x,所以n = 2x +1
AC CODE

//Memory: 935 KB Time: 31 MS//Language: GNU CPP (MinGW, GCC 4) Result: Accepted#include <iostream>#include <string>#include <cstdio>#include <cmath>#include <cstring>#include <algorithm>#define LL long long#define MAXI 2147483647#define MAXL 9223372036854775807#define eps (1e-8)#define dg(i) cout << "*" << i << endl;using namespace std;int main(){    LL x;    while(scanf("%I64d", &x) != EOF)    {        printf("%I64d\n", 2 * x + 1);    }    return 0;}