#include <iostream>
#include <cstdio>
#include <vector>
#include <map>
#include <set>
#include <algorithm>
#include <string>
#include <cstdlib>
#include <stack>
#include <queue>
#include <cmath>
using namespace std;

int main() {
	char c[3] = { 'A','B','C' };
	int n[3];
	for (int i = 0; i <3 ; i++)cin >> n[i];

	for (int i = 0; i < 2; i++) {
		for (int j = i + 1; j < 3; j++) {
			if (n[i] > n[j]) {
				int swap;
				swap = n[i];
				n[i] = n[j];
				n[j] = swap;

				char swapp;
				swapp = c[i];
				c[i] = c[j];
				c[j] = swapp;
			}
		}
	}

	for (int i = 2; i >= 0; i--)cout << c[i] << endl;

}