//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int siz(string s){
  return (int)s.size();
}

int main(){
  vector<vector<int>> X(3, vector<int>(2));
  for(int i = 0; i < 3; i++) cin >> X[i][0] >> X[i][1];

  vector<int> rank(3, 1);
  for(int i = 0; i < 3; i++){
    for(int j = i+1; j < 3; j++){
      if(X[i][0] > X[j][0] or (X[i][0] == X[j][0] and X[i][1] < X[j][1])){
        rank[j]++;
      }else{
        rank[i]++;
      }
    }
  }

  for(int i = 1; i <= 3; i++){
    for(int j = 0; j < 3; j++){
      if(rank[j] == i){
        switch(j){
          case 0: printl('A'); break;
          case 1: printl('B'); break;
          case 2: printl('C'); break;
        }
      }
    }
  }

  return 0;
}