#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main(void) {
	vector<pair<int, int> > h(3);
	for (int i = 0; i < 3; ++i) {
		cin >> h[i].first;
		h[i].second = i;
	}
	sort(h.begin(), h.end(), greater<pair<int, int> >());
	for (int i = 0; i < 3; ++i) {
		if (h[i].second == 0) cout << "A\n";
		else if (h[i].second == 1) cout << "B\n";
		else if (h[i].second == 2) cout << "C\n";
	}
	return 0;
}