#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(LL i = a;i<b; i++)
#define rrep(i,a,b) for(LL i = a;i>b; i--)
#define INF ((1LL<<62)-(1LL<<31))
#define ooki 9,223,372,036,854,775,807
#define tii -9,223,372,036,854,775,808
typedef long long LL;
int main(){
 vector<pair<int,char>> f(3);
 int n;
 cin >> n;
 f[0]={n,'A'};
 cin>>n;
 f[1]={n,'B'};
 cin>>n;
 f[2]={n,'C'};
 sort(f.begin(),f.end());
 reverse(f.begin(),f.end());
 rep(i,0,3){
   cout<<f[i].second<<endl;
 }
  
}