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

int main() {
	int H[3];
	map<int, char> mp;
	cin >> H[0] >> H[1] >> H[2];
	mp[H[0]] = 'A';
	mp[H[1]] = 'B';
	mp[H[2]] = 'C';
	sort(H, H + 3, greater<int>());
	for (int i = 0; i < 3; i++) {
		cout << mp[H[i]] << endl;
	}
}