#include <iostream>
#include <vector>
#include <algorithm> 
#include <queue>
#include <functional>
#include <map>
#include <string>
using namespace std;

typedef long long ll;



int main(void){

    int A, B, C;
    cin >> A >> B >> C;
    int a[3] = { A, B, C };
    sort(a, a + 3);

    for (int i = 2; i >= 0; i--){
        if (a[i] == A){
            cout << 'A' << endl;
        }
        else if (a[i] == B){
            cout << 'B' << endl;
        }
        else{
            cout << 'C' << endl;
        }
    }




}