import java.util.*;

public class Main {
	public static void main (String[] args) {
    	Scanner sc = new Scanner(System.in);
    	Person[] arr = new Person[3];
    	for (int i = 0; i < 3; i++) {
    	    arr[i] = new Person((char)(i + 'A'), sc.nextInt());
    	}
    	Arrays.sort(arr);
    	StringBuilder sb = new StringBuilder();
    	for (Person p : arr) {
    	    sb.append(p.name).append("\n");
    	}
    	System.out.print(sb);
    }
    
    static class Person implements Comparable<Person> {
        char name;
        int height;
        
        public Person(char name, int height) {
            this.name = name;
            this.height = height;
        }
        
        public int compareTo(Person another) {
            return another.height - height;
        }
    }

}