#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <map>
#include <math.h>
using namespace std;
typedef long long int ll;

int main(){
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	int a,b,c; cin >> a >> b >> c;
	vector<pair<int,char> > v;
	v.push_back(make_pair(a,'A'));
	v.push_back(make_pair(b,'B'));
	v.push_back(make_pair(c,'C'));
	sort(v.begin(),v.end());
	for(int i=2;i>=0;i--){
		cout << v[i].second << endl;
	}
}