#include <bits/stdc++.h>

using namespace std;

struct bro {
  int H, W;
  int name;
  bro(): H(0), W(0), name(0) {}
  bro(int h, int w, int n): H(h), W(w), name(n) {}

  bool operator<(const bro &a) const {
    if (H == a.H) return W > a.W;
    return H < a.H;
  }
};

int main() {
  bro bros[3];
  for (int i = 0; i< 3; ++i) {
    int h, w;
    scanf("%d %d", &h, &w);
    bros[i] = bro(h, w, i);
  }

  sort(bros, bros + 3);
  for (int i = 2; i >= 0; --i) {
    if (bros[i].name == 0) cout << 'A';
    else if (bros[i].name == 1) cout << 'B';
    else cout << 'C';
    puts("");
  }
  return 0;
}