#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;

tuple<int, int, char> HW[3];

int main() {
  for (int i = 0; i < 3; i++) {
    int H, W;
    cin >> H >> W;
    get<0>(HW[i]) = H;
    get<1>(HW[i]) = W;
    get<2>(HW[i]) = char('A' + i);
  }
  sort(HW, HW + 3, [](auto a, auto b) {
    if (get<0>(a) == get<0>(b)) {
      return get<1>(a) < get<1>(b);
    }
    return get<0>(a) > get<0>(b);
  });
  for (int i = 0; i < 3; i++) {
    cout << get<2>(HW[i]) << endl;
  }
  return 0;
}