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

#define REP(i,n) for(int i=0;(i)<(n);(i)++)
#define ll long long

int main() {
	pair<int,char> a[3];
	
	REP(i, 3) {
		cin >> a[i].first;
		a[i].second = 'A' + i;
	}
	
	sort(a, a + 3);

	for(int i=2;i>=0;i--) {
		cout << a[i].second << endl;
	}


	return 0;
}