#include <bits/stdc++.h>
using namespace std;

int main() {
	vector<vector<int>> v(3, vector<int>(2));
	for (int i = 0; i < 3; i++) {
		cin >> v.at(i).at(0);
		if (i == 0) {
			v.at(i).at(1) = 1;
		}
		else if (i == 1) {
			v.at(i).at(1) = 2;
		}
		else if (i == 2) {
			v.at(i).at(1) = 3;
		}
	}

	sort(v.begin(), v.end());
	reverse(v.begin(), v.end());

	for (int i = 0; i < 3; i++) {
		int n = v.at(i).at(1);
		if (n == 1) cout << "A" << endl;
		if (n == 2) cout << "B" << endl;
		if (n == 3) cout << "C" << endl;
	}
}