#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  vector<pair<int, int>> v(3);
  rep(i, 3) {
    cin >> v[i].first >> v[i].second;
    v[i].first *= -1;
  }
  vector<int> p = { 0, 1, 2 };
  sort(p.begin(), p.end(), [&](int i, int j) {
    return v[i] < v[j];
  });
  for (int i : p) cout << (char) ('A' + i) << endl;
  return 0;
}