#include <iostream>
#include <vector>
#include <algorithm>
#include <utility>

using namespace std;
using PIC = pair<int, char>;

int main() {
	int h;
	vector<PIC> people(3);
	for (int i = 0; i < 3; i++) {
		cin >> h;
		people[i] = make_pair(h, 'A' + i);
	}

	sort(people.begin(), people.end(), greater<PIC>());
	for (auto x: people) {
		cout << x.second << endl;
	}

	return 0;
}