#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <sstream>
#include <complex>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <cmath>
#include <cassert>
#include <fstream>
#define REP(i,n) for(int i=0;i<n;i++)
#define FOR(a,b) for(:a<b;a++)
#define SSTR( x ) static_cast< std::ostringstream & >( \
        ( std::ostringstream() << std::dec << x ) ).str()
#define ALL(s) (s).begin(), (s).end()
using namespace std;
typedef long long unsigned int llu;
typedef long long ll;

int main (){
  vector <int> in;
  int A,B,C;
  while (cin >> A){
    in.push_back(A);
    cin >> B;
    in.push_back(B);
    cin >> C;
    in.push_back(C);
    sort(ALL(in));
    reverse(ALL(in));
    REP(i,3){
      if(in[i] == A){
	cout << "A" << endl;
      }else if(in[i] == B){
	cout << "B" << endl;
      }else{
	cout << "C" << endl;
      }
    }
    in.clear();
  }
  return 0;
}