#include <bits/stdc++.h>
#define rep(i,n)for(long long i=0;i<(n);i++)
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
const ll INF=1e18;
const int MOD=1e9+7;
const double pi=acos(-1);

int main(){
  vector<pair<int,char>>vec;
  rep(i,3){
    int a;
    cin >> a;
    vec.push_back(make_pair(a,char('A'+i)));
  }
  sort(vec.begin(),vec.end(),greater<pair<int,char>>());
  rep(i,3){
    cout << vec[i].second << endl;
  }
}