import java.util.*;


public class Main 
{

	public static void main(String[] args) 
	{
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		
		int sum1 = 0, sum2 = 0, count1 = 1, count2 = 2;
		for(int i = 0; i < n; i++)
		{
			sum1 += Math.abs(arr[i]-count1);
			count1 += 2;
		}
		for(int i = 0; i < n; i++)
		{
			sum2 += Math.abs(arr[i]-count2);
			count2 += 2;
		}
		if(count1 <= count2)
			System.out.println(count1);
		else
			System.out.println(count2);
	}

}
