#include "bits/stdc++.h"

using namespace std;
using ll = long long;
using IP = pair<int, int>;

#define INF 999999999
#define atcoder(int)1e9+7

int main() {

	vector<pair<int, char>>l(3);

	for (int i = 0; i < 3; i++) {
		cin >> l[i].first;
		l[i].second = 'A' + i;
	}
	sort(l.begin(), l.end());

	for (int i = 2; i >=0; i--) {
		cout << l[i].second << endl;
	}

	return 0;
}