#include <iostream>
#include <vector>
#include <algorithm>
#include <utility>
using namespace std;

int main(void){
  vector<pair<int, char> > p(3);
  int h;
  for(int i = 0; i < 3; i++){
    cin >> h;
    p[i] = make_pair(h, 'A' + i);
  }
  sort(p.begin(), p.end());
  for(int i = 2; i >= 0; i--) cout << p[i].second << endl;
  return 0;
}