#include <bits/stdc++.h>

using namespace std;
typedef pair<int, char> P;

int main() {
  priority_queue<P> q;
  for (int i = 0; i < 3; ++i) {
    int h;
    cin >> h;
    q.emplace(h, 'A' + i);
  }

  while (!q.empty()) {
    P cur = q.top();q.pop();
    cout << cur.second << '\n';
  }
  return 0;
}