#include <bits/stdc++.h>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  vector<char> S = {'A', 'B', 'C'};
  vector<int> H(3);
  for (int &x : H) {
    cin >> x;
  }
  vector<int> idx(3);
  iota(idx.begin(), idx.end(), 0);
  sort(idx.begin(), idx.end(), [&](int a, int b) { return H[a] > H[b]; });
  for (int i : idx) {
    cout << S[i] << '\n';
  }
  return 0;
}