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"
        };
        string[] str=new string[3];
        int i=0;
            foreach(var key in dic.Keys){
                str[i]=dic[key];
                i++;
            }
        for(int j=3;j>0;--j){
            Console.WriteLine(str[j-1]);
        }
    }
}