import java.io.*;
import java.util.*;
class Main
{
	public static void main(String args[]) throws Exception
	{
		Scanner cin=new Scanner(System.in);
		int i,n,sum,p;
		n=cin.nextInt();
		for(i=1,sum=-n;;i++)
		{
			sum+=i;
			if(sum>=0&&sum%2==0) break;
			
		}
		System.out.println(i);
	}
}