#include <bits/stdc++.h>
#define REP(i,a,b) for(int i=(a);i<(b);i++)
#define RREP(i,a,b) for(int i=(a);i>=(b);i--)
typedef long long ll; typedef long double ld;
using namespace std;
const int INF=1e9, MOD=1e9+7, mod=998244353;
int a;
vector<pair<int,char>> vec;
 
int main(){
	cin >> a; vec.push_back(make_pair(a,'A'));
	cin >> a; vec.push_back(make_pair(a,'B'));
	cin >> a; vec.push_back(make_pair(a,'C'));
	sort(vec.rbegin(),vec.rend());
	REP(i,0,3) cout << vec[i].second << endl;
	return 0;
}