#include <bits/stdc++.h>
using namespace std;

typedef tuple< int, int, char > height;

int main(void)
{
  vector< height > h(3);
  for (int i = 0; i < 3; ++i) {
    int he, w;
    cin >> he >> w;
    h[i] = make_tuple(he, -w, 'A'+i);
  }
  sort(h.begin(), h.end());
  cout << get<2>(h[2]) << endl << get<2>(h[1]) << endl << get<2>(h[0]) << endl;
  return 0;
}