#include <iostream>
#include <algorithm>
using namespace std;

int main(){
	pair<int, char> p[3];
	for(int i = 0; i < 3; i++){
		cin >> p[i].first;
		p[i].second = "ABC"[i];
	}
	sort(p, p + 3);
	reverse(p, p + 3);
	for(int i = 0; i < 3; i++){
		cout << p[i].second << endl;
	}
	return 0;
}