using System;
public class Power
{
	public static void Main()
	{
		int num;
		int power=0;
		Console.WriteLine("Enter a number: ");
		num=int.Parse(Console.ReadLine());
		while(power*2<=num)
		{
		if(num>power)
		power=power+1;
		else
			Console.WriteLine(power);
		}
		Console.ReadLine();
			
		
	}
}