#include <iostream>
#include <cstdio>
#include <algorithm>
#include <string>
#include <cstring>
#include <cctype>
#include <cmath>
#include <stack>
#include <queue>
#include <vector>
#include <set>
#include <map>
#include <list>
#include <stdio.h>
#include <string.h>
#include <cstdlib>
#include <math.h>
#include <bitset>
#include <iterator>
#include <iomanip>
#include <sstream>
#define INF 2000000000
using namespace std;
int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
#define sym cout<<"---------"<<endl;
#define ll long long
#define PL pair<long long, long long>
#define P pair<int,int>
#define mk make_pair
#define en endl
#define WHITE 0
#define BLACK 2
#define GRAY 1
#define RE return 0
//#define int ll


signed main(){
  pair<int, int> a[3];
  cin>>a[0].first>>a[1].first>>a[2].first;
  a[0].second=0; a[1].second=1; a[2].second=2;
  sort(a, a+3,greater<P>());
  for(int i=0; i<3; i++){
    if(a[i].second==0){
      cout<<'A'<<en;
    }else if(a[i].second==1){
      cout<<'B'<<en;
    }else{
      cout<<'C'<<en;
    }
  }
}