class Main{
	public static long func(long n){
		if(n <= 100){
			return 91;
		}
		else {
			return n - 10;
		}
	}
	public static void main (String[] args){
		java.util.Scanner in = new java.util.Scanner(System.in);
		long num = in.nextInt();
		System.out.println(func(num));
	}
}