#include<bits/stdc++.h>
#define rep(i, x) for(ll i = 0; i < x; i++)
#define rep2(i, x) for(ll i = 1; i <= x; i++)
#define all(a) (a).begin(),(a).end()
using ll = long long;
using ld = long double;
const ll INF = 10000000000000000;
using namespace std;
signed main() {
    typedef pair <ll, char> p; vector<p> v(3);
	cin >> v[0].first >> v[1].first >> v[2].first;
	v[0].second = 'A'; v[1].second = 'B'; v[2].second = 'C';
	sort(all(v)); reverse(all(v));
	rep(i, 3) { cout << v[i].second << endl; }
	return 0;
}