import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int[] h = new int[3];
    int[] w = new int[3];
    for(int i = 0; i < 3; i++) {
      h[i] = sc.nextInt();
      w[i] = sc.nextInt();
    }
    int[] ord = new int[3];

    if(h[0] > h[1]) {
      ord[0]++;
    } else if(h[0] < h[1]) {
      ord[1]++;
    } else {
      if(w[0] < w[1]) {
        ord[0]++;
      } else {
        ord[1]++;
      }
    }

    if(h[0] > h[2]) {
      ord[0]++;
    } else if(h[0] < h[2]) {
      ord[2]++;
    } else {
      if(w[0] < w[2]) {
        ord[0]++;
      } else {
        ord[2]++;
      }
    }

    if(h[2] > h[1]) {
      ord[2]++;
    } else if(h[2] < h[1]) {
      ord[1]++;
    } else {
      if(w[2] < w[1]) {
        ord[2]++;
      } else {
        ord[1]++;
      }
    }

    for(int i = 2; i >= 0; i--) {
      if(ord[0] == i) System.out.println("A");
      if(ord[1] == i) System.out.println("B");
      if(ord[2] == i) System.out.println("C");
    }
  }
}