using System;
using System.Collections.Generic;

class No570{
    static void Main(string[] args){
        var dic =new SortedDictionary<string,string>(){
            [$"{Console.ReadLine()}"]="A",
            [$"{Console.ReadLine()}"]="B",
            [$"{Console.ReadLine()}"]="C"
        };
            foreach(var key in dic.Keys){
                Console.WriteLine($"{dic[key]}");
            }
        

    }
}