import java.util.Scanner

object Main {

  def calc(xs: Array[Array[Int]]) {
    val ys = xs.sortWith((a, b) =>
    {
      val c = a(0).compare(b(0))
      if (c == 0) a(1).compareTo(b(1)) < 0 else -a(0).compareTo(b(0)) < 0
    });

    for (y <- ys)
      println((y(2) + 'A').toChar)
  }

  def main(args: Array[String]) {
    val sc = new Scanner(System.in)
    val x1, y1, x2, y2, x3, y3 = sc.nextInt()

    var xs = Array(Array(x1, y1, 0), Array(x2, y2, 1), Array(x3, y3, 2))
    calc(xs)
  }
}