#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,string> P;

signed main(){
  set<P> s;
  int a;cin>>a;s.insert(P(-a,"A"));
  cin>>a;s.insert(P(-a,"B"));
  cin>>a;s.insert(P(-a,"C"));
  for(auto p:s)cout<<p.second<<endl;
}