import java.util.Scanner;

public class SwitchExample {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int input;
		char output;

		input = sc.nextInt();

		switch(input) {
		case 1: output='A'; break;
		case 2: output='B'; break;
		case 3: output='C'; break;
		case 4: output='D'; break;
		default: output='-';
		}

		System.out.println(output);
	}

}

/*

See what happens if you remove one of the "break;" statements.  
Then change 
        case 4: output='D'; break;
to be this instead
        case 4: case 7: output='D'; break;
and see whether 4 or 7 will get that code to run.  

What about the following for a char value?
        case 'a': case 'A': code to run....

 */





//Copyright 2010-2012 : Evan Golub