using System;
using System.Linq;
using System.Text;
using System.Collections.Generic;
using STR = System.String;
using INT = System.Int32;
using DEC = System.Double;

class Program
{
    public static IO IO = new IO();
    static void Main(string[] args)
    {
        INT[] abc = IO.I(3);
        INT max = INT.MinValue;
        INT min = INT.MaxValue;
        char[] o = new char[3] { 'A', 'B', 'C' };
        INT x = 0;
        INT y = 0;
        for (int i = 0; i < 3; i++)
        {
            if (max < abc[i]) { max = abc[i]; x = i; }
            if (min > abc[i]) { min = abc[i]; y = i; }
        }
        INT z = 3 - (x + y);
        IO.W(o[x]);
        IO.W(o[z]);
        IO.W(o[y]);
        IO.F();
    }
}

public class IO
{
    private const int WMAX = 1000;
    private StringBuilder SB = new StringBuilder();
    private T R<T>(Func<STR, T> f) { return f(Console.ReadLine()); }
    private T[] R<T>(Func<STR, T> f, char c) { return S().Split(c).Select(f).ToArray(); }
    private T[] R<T>(Func<STR, T> f, INT l) { T[] r = new T[l]; for (INT i = 0; i < l; i++) { r[i] = R(f); } return r; }
    private T[][] R<T>(Func<STR, T> f, INT l, char c) { T[][] r = new T[l][]; for (INT i = 0; i < l; i++) { r[i] = R<T>(f, c); } return r; }
    private void W<T>(Func<T, STR> f, T v, bool lf = true) { SB.Append(f(v)); if (lf) { SB.Append('\n'); } if (SB.Length >= WMAX) { F(); } }
    public STR S() { return R(s => s); }
    public STR[] S(char c) { return R(s => s, c); }
    public STR[] S(INT l) { return R(s => s, l); }
    public STR[][] S(INT l, char c) { return R(s => s, l, c); }
    public INT I() { return R(INT.Parse); }
    public INT[] I(char c) { return R(INT.Parse, c); }
    public INT[] I(INT l) { return R(INT.Parse, l); }
    public INT[][] I(INT l, char c) { return R(INT.Parse, l, c); }
    public DEC D() { return R(DEC.Parse); }
    public DEC[] D(char c) { return R(DEC.Parse, c); }
    public DEC[] D(INT l) { return R(DEC.Parse, l); }
    public DEC[][] D(INT l, char c) { return R(DEC.Parse, l, c); }
    public void W(object s, bool lf = true) { W(v => v.ToString(), s, lf); }
    public void F() { Console.Write(SB); SB.Length = 0; }
}