1 + 2 + 3 + . . . + n = k

Time Limit: 1 sec

 

The Problem

Given the following formula, in order to obtain a given k, you need to find the value of n.

1 + 2 + 3 + ... + n = k

 

 

For example:

Given k = 15, the expression to be used will be

1 + 2 + 3 + 4 + 5 = 15       Here, n = 5

 

The Input

Input file contain a series of line, each line contain one integers k (0< =k <=1000405). Input is terminated by EOF.

 

The Output

For each line of input, your program should print the minimal possible n (1<=n) to obtain k with the above formula.

 

Sample Input

15

5050

6

 

Sample Output

5

100

3

 

 

 

 

Problem Setter: Shahin ShamS